From DOE’s SLAC National Accelerator Laboratory (US) : “Experiments confirm a quantum material’s unique response to circularly polarized laser light” 

From DOE’s SLAC National Accelerator Laboratory (US)

October 22, 2021
Glennda Chui

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This pattern of arrows reflects the combined spin and momentum of electrons in the surface layer of a topological insulator, a quantum material that conducts electric current on its surface but not through its interior. Experiments at SLAC discovered that circularly polarized laser light couples to this spin polarization to produce a unique pattern of high harmonic generation that is a signature of topological surfaces. Credit: Denitsa Baykusheva/Stanford PULSE Institute)

When the COVID-19 pandemic shut down experiments at the Department of Energy’s SLAC National Accelerator Laboratory early last year, Shambhu Ghimire’s research group was forced to find another way [Physical Review A] to study an intriguing research target: quantum materials known as topological insulators, or TIs, which conduct electric current on their surfaces but not through their interiors.

Denitsa Baykusheva, a Swiss National Science Foundation [Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung] [Fonds national suisse de la recherche scientifique] (CH) Fellow, had joined his group at the Stanford PULSE Institute two years earlier with the goal of finding a way to generate high harmonic generation, or HHG, in these materials as a tool for probing their behavior. In HHG, laser light shining through a material shifts to higher energies and higher frequencies, called harmonics, much like pressing on a guitar string produces higher notes. If this could be done in TIs, which are promising building blocks for technologies like spintronics, quantum sensing and quantum computing, it would give scientists a new tool for investigating these and other quantum materials.

With the experiment shut down midway, she and her colleagues turned to theory and computer simulations to come up with a new recipe for generating HHG in topological insulators. The results suggested that circularly polarized light, which spirals along the direction of the laser beam, would produce clear, unique signals from both the conductive surfaces and the interior of the TI they were studying, bismuth selenide – and would in fact enhance the signal coming from the surfaces.

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Laser light is usually linearly polarized, meaning that its waves oscillate in only one direction – up and down, in the example at left. But it can also be circularly polarized, at right, so its waves spiral like a corkscrew around the direction the light is traveling. A new study from SLAC and Stanford predicts that this circularly polarized light can be used to explore quantum materials in ways that were not possible before. (Greg Stewart/SLAC National Accelerator Laboratory.)

When the lab reopened for experiments with covid safety precautions in place, Baykusheva set out to test that recipe for the first time. In a paper published today in Nano Letters, the research team reported that those tests went exactly as predicted, producing the first unique signature from the topological surface.

“This material looks very different than any other material we’ve tried,” said Ghimire, who is a principal investigator at PULSE. “It’s really exciting being able to find a new class of materials that has a very different optical response than anything else.”

Over the past dozen years, Ghimire had done a series of experiments with PULSE Director David Reis showing that HHG can be produced in ways that were previously thought unlikely or even impossible: by beaming laser light into a crystal, a frozen argon gas or an atomically thin semiconductor [Nature Physics] material. Another study described how to use HHG to generate attosecond laser pulses, which can be used to observe and control the movements of electrons, by shining a laser through ordinary glass.

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An illustration shows how circularly polarized laser light (top) is used to probe a topological insulator (black), a quantum material that conducts electric current on its surface but not through its interior. The light causes electrons in the material to fly apart, recombine and emit light (white) of higher energies and frequencies through a process called high harmonic generation. By analyzing this emitted light, scientists can measure the spin and momentum of electrons in the material. Experiments at SLAC confirm that these signals are a unique signature of topological surfaces. (Greg Stewart/SLAC National Accelerator Laboratory.)

But quantum materials had steadfastly resisted being analyzed this way, and the split personalities of topological insulators presented a particular problem.

“When we shine laser light on a TI, both the surface and the interior produce harmonics. The challenge is to separate them,” Ghimire said.

The team’s key discovery, he explained, was that circularly polarized light interacts with the surface and the interior in profoundly different ways that boost high harmonic generation coming from the surface and also give it a distinctive signature. Those interactions, in turn, are shaped by two fundamental differences between the surface and the interior: the degree to which their electron spins are polarized ­– oriented in a clockwise or counterclockwise direction, for instance – and the types of symmetry found in their atomic lattices.

Since the group published their recipe for achieving HHG in TIs earlier this year, two other research groups in Germany and China have reported creating HHG in a topological insulator, Ghimire said. But both of those experiments were with linearly polarized light, so they did not see the enhanced signal generated by circularly polarized light. That signal, he said, is a unique feature of topological surface states.

Because intense laser light can turn electrons in a material into a soup of electrons – a plasma – the team had to find a way to shift the wavelength of their high-powered titanium sapphire laser so it was 10 times longer, and thus 10 times less energetic. They also used very short laser pulses to minimize damage to the sample, which had the added advantage of allowing them to capture the material’s behavior with the equivalent of a shutter speed of millionths of a billionth of a second.

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Diagram of an experimental setup at SLAC’s high-power laser lab where scientists used circularly polarized laser light to probe a topological insulator – a type of quantum material that conducts electric current on its surfaces but not through its interior. A process called high harmonic generation shifts the laser light to higher energies and frequencies, or harmonics. This produces polarization patterns in a detector (arrows) that reveal the spin and momentum of electrons in the conductive surface layer – a unique signature of the topological surface. (Shambhu Ghimire/Stanford PULSE Institute.)

“The advantage of using HHG is that it’s an ultrafast probe,” Ghimire said. “Now that we’ve identified this novel approach to probing the topological surface states, we can use it to study other interesting materials, including topological states induced by strong lasers or by chemical means.”

Researchers from the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC, The University of Michigan (US), and Pohang University of Science and Technology [성실; 창의; 진취](KR) contributed to this work. Major funding came from the DOE Office of Science, including an Early Career Research Program award to Shambhu Ghimire, and from the Swiss National Science Foundation.

See the full article here .


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SLAC National Accelerator Laboratory (US) originally named Stanford Linear Accelerator Center, is a Department of Energy (US) National Laboratory operated by Stanford University (US) under the programmatic direction of the Department of Energy (US) Office of Science and located in Menlo Park, California. It is the site of the Stanford Linear Accelerator, a 3.2 kilometer (2-mile) linear accelerator constructed in 1966 and shut down in the 2000s, which could accelerate electrons to energies of 50 GeV.
Today SLAC research centers on a broad program in atomic and solid-state physics, chemistry, biology, and medicine using X-rays from synchrotron radiation and a free-electron laser as well as experimental and theoretical research in elementary particle physics, astroparticle physics, and cosmology.

Founded in 1962 as the Stanford Linear Accelerator Center, the facility is located on 172 hectares (426 acres) of Stanford University-owned land on Sand Hill Road in Menlo Park, California—just west of the University’s main campus. The main accelerator is 3.2 kilometers (2 mi) long—the longest linear accelerator in the world—and has been operational since 1966.

Research at SLAC has produced three Nobel Prizes in Physics

1976: The charm quark—see J/ψ meson
1990: Quark structure inside protons and neutrons
1995: The tau lepton

SLAC’s meeting facilities also provided a venue for the Homebrew Computer Club and other pioneers of the home computer revolution of the late 1970s and early 1980s.

In 1984 the laboratory was named an ASME National Historic Engineering Landmark and an IEEE Milestone.

SLAC developed and, in December 1991, began hosting the first World Wide Web server outside of Europe.

In the early-to-mid 1990s, the Stanford Linear Collider (SLC) investigated the properties of the Z boson using the Stanford Large Detector.

As of 2005, SLAC employed over 1,000 people, some 150 of whom were physicists with doctorate degrees, and served over 3,000 visiting researchers yearly, operating particle accelerators for high-energy physics and the Stanford Synchrotron Radiation Laboratory (SSRL) for synchrotron light radiation research, which was “indispensable” in the research leading to the 2006 Nobel Prize in Chemistry awarded to Stanford Professor Roger D. Kornberg.

In October 2008, the Department of Energy announced that the center’s name would be changed to SLAC National Accelerator Laboratory. The reasons given include a better representation of the new direction of the lab and the ability to trademark the laboratory’s name. Stanford University had legally opposed the Department of Energy’s attempt to trademark “Stanford Linear Accelerator Center”.

In March 2009, it was announced that the SLAC National Accelerator Laboratory was to receive $68.3 million in Recovery Act Funding to be disbursed by Department of Energy’s Office of Science.

In October 2016, Bits and Watts launched as a collaboration between SLAC and Stanford University to design “better, greener electric grids”. SLAC later pulled out over concerns about an industry partner, the state-owned Chinese electric utility.

Accelerator

The main accelerator was an RF linear accelerator that accelerated electrons and positrons up to 50 GeV. At 3.2 km (2.0 mi) long, the accelerator was the longest linear accelerator in the world, and was claimed to be “the world’s most straight object.” until 2017 when the European x-ray free electron laser opened. The main accelerator is buried 9 m (30 ft) below ground and passes underneath Interstate Highway 280. The above-ground klystron gallery atop the beamline, was the longest building in the United States until the LIGO project’s twin interferometers were completed in 1999. It is easily distinguishable from the air and is marked as a visual waypoint on aeronautical charts.

A portion of the original linear accelerator is now part of the Linac Coherent Light Source [below].

Stanford Linear Collider

The Stanford Linear Collider was a linear accelerator that collided electrons and positrons at SLAC. The center of mass energy was about 90 GeV, equal to the mass of the Z boson, which the accelerator was designed to study. Grad student Barrett D. Milliken discovered the first Z event on 12 April 1989 while poring over the previous day’s computer data from the Mark II detector. The bulk of the data was collected by the SLAC Large Detector, which came online in 1991. Although largely overshadowed by the Large Electron–Positron Collider at CERN, which began running in 1989, the highly polarized electron beam at SLC (close to 80%) made certain unique measurements possible, such as parity violation in Z Boson-b quark coupling.

Presently no beam enters the south and north arcs in the machine, which leads to the Final Focus, therefore this section is mothballed to run beam into the PEP2 section from the beam switchyard.

The SLAC Large Detector (SLD) was the main detector for the Stanford Linear Collider. It was designed primarily to detect Z bosons produced by the accelerator’s electron-positron collisions. Built in 1991, the SLD operated from 1992 to 1998.

SLAC National Accelerator Laboratory(US)Large Detector

PEP

PEP (Positron-Electron Project) began operation in 1980, with center-of-mass energies up to 29 GeV. At its apex, PEP had five large particle detectors in operation, as well as a sixth smaller detector. About 300 researchers made used of PEP. PEP stopped operating in 1990, and PEP-II began construction in 1994.

PEP-II

From 1999 to 2008, the main purpose of the linear accelerator was to inject electrons and positrons into the PEP-II accelerator, an electron-positron collider with a pair of storage rings 2.2 km (1.4 mi) in circumference. PEP-II was host to the BaBar experiment, one of the so-called B-Factory experiments studying charge-parity symmetry.

SLAC National Accelerator Laboratory(US) BaBar

SLAC National Accelerator Laboratory(US)/SSRL

Fermi Gamma-ray Space Telescope

SLAC plays a primary role in the mission and operation of the Fermi Gamma-ray Space Telescope, launched in August 2008. The principal scientific objectives of this mission are:

To understand the mechanisms of particle acceleration in AGNs, pulsars, and SNRs.
To resolve the gamma-ray sky: unidentified sources and diffuse emission.
To determine the high-energy behavior of gamma-ray bursts and transients.
To probe dark matter and fundamental physics.

National Aeronautics and Space Administration(US)/Fermi Large Area Telescope

National Aeronautics and Space Administration(US)/Fermi Gamma Ray Space Telescope.

KIPAC

http://kipac.stanford.edu/kipac/campus

The Stanford PULSE Institute (PULSE) is a Stanford Independent Laboratory located in the Central Laboratory at SLAC. PULSE was created by Stanford in 2005 to help Stanford faculty and SLAC scientists develop ultrafast x-ray research at LCLS.

The Linac Coherent Light Source (LCLS)[below] is a free electron laser facility located at SLAC. The LCLS is partially a reconstruction of the last 1/3 of the original linear accelerator at SLAC, and can deliver extremely intense x-ray radiation for research in a number of areas. It achieved first lasing in April 2009.

The laser produces hard X-rays, 10^9 times the relative brightness of traditional synchrotron sources and is the most powerful x-ray source in the world. LCLS enables a variety of new experiments and provides enhancements for existing experimental methods. Often, x-rays are used to take “snapshots” of objects at the atomic level before obliterating samples. The laser’s wavelength, ranging from 6.2 to 0.13 nm (200 to 9500 electron volts (eV)) is similar to the width of an atom, providing extremely detailed information that was previously unattainable. Additionally, the laser is capable of capturing images with a “shutter speed” measured in femtoseconds, or million-billionths of a second, necessary because the intensity of the beam is often high enough so that the sample explodes on the femtosecond timescale.

The LCLS-II [below] project is to provide a major upgrade to LCLS by adding two new X-ray laser beams. The new system will utilize the 500 m (1,600 ft) of existing tunnel to add a new superconducting accelerator at 4 GeV and two new sets of undulators that will increase the available energy range of LCLS. The advancement from the discoveries using this new capabilities may include new drugs, next-generation computers, and new materials.

FACET

In 2012, the first two-thirds (~2 km) of the original SLAC LINAC were recommissioned for a new user facility, the Facility for Advanced Accelerator Experimental Tests (FACET). This facility was capable of delivering 20 GeV, 3 nC electron (and positron) beams with short bunch lengths and small spot sizes, ideal for beam-driven plasma acceleration studies. The facility ended operations in 2016 for the constructions of LCLS-II which will occupy the first third of the SLAC LINAC. The FACET-II project will re-establish electron and positron beams in the middle third of the LINAC for the continuation of beam-driven plasma acceleration studies in 2019.

SLAC National Accelerator Laboratory(US) FACET

SLAC National Accelerator Laboratory(US) FACET-II upgrading its Facility for Advanced Accelerator Experimental Tests (FACET) – a test bed for new technologies that could revolutionize the way we build particle accelerators.

The Next Linear Collider Test Accelerator (NLCTA) is a 60-120 MeV high-brightness electron beam linear accelerator used for experiments on advanced beam manipulation and acceleration techniques. It is located at SLAC’s end station B

SLAC National Accelerator Laboratory(US) Next Linear Collider Test Accelerator (NLCTA)

DOE’s SLAC National Accelerator Laboratory campus

SLAC National Accelerator Laboratory(US)/LCLS

SLAC National Accelerator Laboratory(US)/LCLS II projected view

Magnets called undulators stretch roughly 100 meters down a tunnel at SLAC National Accelerator Laboratory, with one side (right) producing hard x-rays and the other soft x-rays.Credit: SLAC National Accelerator Laboratory.

SSRL and LCLS are DOE Office of Science user facilities.

Stanford University (US)

Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members.

Stanford University, officially Leland Stanford Junior University, is a private research university located in Stanford, California. Stanford was founded in 1885 by Leland and Jane Stanford in memory of their only child, Leland Stanford Jr., who had died of typhoid fever at age 15 the previous year. Stanford is consistently ranked as among the most prestigious and top universities in the world by major education publications. It is also one of the top fundraising institutions in the country, becoming the first school to raise more than a billion dollars in a year.

Leland Stanford was a U.S. senator and former governor of California who made his fortune as a railroad tycoon. The school admitted its first students on October 1, 1891, as a coeducational and non-denominational institution. Stanford University struggled financially after the death of Leland Stanford in 1893 and again after much of the campus was damaged by the 1906 San Francisco earthquake. Following World War II, provost Frederick Terman supported faculty and graduates’ entrepreneurialism to build self-sufficient local industry in what would later be known as Silicon Valley.

The university is organized around seven schools: three schools consisting of 40 academic departments at the undergraduate level as well as four professional schools that focus on graduate programs in law, medicine, education, and business. All schools are on the same campus. Students compete in 36 varsity sports, and the university is one of two private institutions in the Division I FBS Pac-12 Conference. It has gained 126 NCAA team championships, and Stanford has won the NACDA Directors’ Cup for 24 consecutive years, beginning in 1994–1995. In addition, Stanford students and alumni have won 270 Olympic medals including 139 gold medals.

As of October 2020, 84 Nobel laureates, 28 Turing Award laureates, and eight Fields Medalists have been affiliated with Stanford as students, alumni, faculty, or staff. In addition, Stanford is particularly noted for its entrepreneurship and is one of the most successful universities in attracting funding for start-ups. Stanford alumni have founded numerous companies, which combined produce more than $2.7 trillion in annual revenue, roughly equivalent to the 7th largest economy in the world (as of 2020). Stanford is the alma mater of one president of the United States (Herbert Hoover), 74 living billionaires, and 17 astronauts. It is also one of the leading producers of Fulbright Scholars, Marshall Scholars, Rhodes Scholars, and members of the United States Congress.

Stanford University was founded in 1885 by Leland and Jane Stanford, dedicated to Leland Stanford Jr, their only child. The institution opened in 1891 on Stanford’s previous Palo Alto farm.

Jane and Leland Stanford modeled their university after the great eastern universities, most specifically Cornell University. Stanford opened being called the “Cornell of the West” in 1891 due to faculty being former Cornell affiliates (either professors, alumni, or both) including its first president, David Starr Jordan, and second president, John Casper Branner. Both Cornell and Stanford were among the first to have higher education be accessible, nonsectarian, and open to women as well as to men. Cornell is credited as one of the first American universities to adopt this radical departure from traditional education, and Stanford became an early adopter as well.

Despite being impacted by earthquakes in both 1906 and 1989, the campus was rebuilt each time. In 1919, The Hoover Institution on War, Revolution and Peace was started by Herbert Hoover to preserve artifacts related to World War I. The Stanford Medical Center, completed in 1959, is a teaching hospital with over 800 beds. The DOE’s SLAC National Accelerator Laboratory(US)(originally named the Stanford Linear Accelerator Center), established in 1962, performs research in particle physics.

Land

Most of Stanford is on an 8,180-acre (12.8 sq mi; 33.1 km^2) campus, one of the largest in the United States. It is located on the San Francisco Peninsula, in the northwest part of the Santa Clara Valley (Silicon Valley) approximately 37 miles (60 km) southeast of San Francisco and approximately 20 miles (30 km) northwest of San Jose. In 2008, 60% of this land remained undeveloped.

Stanford’s main campus includes a census-designated place within unincorporated Santa Clara County, although some of the university land (such as the Stanford Shopping Center and the Stanford Research Park) is within the city limits of Palo Alto. The campus also includes much land in unincorporated San Mateo County (including the SLAC National Accelerator Laboratory and the Jasper Ridge Biological Preserve), as well as in the city limits of Menlo Park (Stanford Hills neighborhood), Woodside, and Portola Valley.

Non-central campus

Stanford currently operates in various locations outside of its central campus.

On the founding grant:

Jasper Ridge Biological Preserve is a 1,200-acre (490 ha) natural reserve south of the central campus owned by the university and used by wildlife biologists for research.
SLAC National Accelerator Laboratory is a facility west of the central campus operated by the university for the Department of Energy. It contains the longest linear particle accelerator in the world, 2 miles (3.2 km) on 426 acres (172 ha) of land.
Golf course and a seasonal lake: The university also has its own golf course and a seasonal lake (Lake Lagunita, actually an irrigation reservoir), both home to the vulnerable California tiger salamander. As of 2012 Lake Lagunita was often dry and the university had no plans to artificially fill it.

Off the founding grant:

Hopkins Marine Station, in Pacific Grove, California, is a marine biology research center owned by the university since 1892.
Study abroad locations: unlike typical study abroad programs, Stanford itself operates in several locations around the world; thus, each location has Stanford faculty-in-residence and staff in addition to students, creating a “mini-Stanford”.

Redwood City campus for many of the university’s administrative offices located in Redwood City, California, a few miles north of the main campus. In 2005, the university purchased a small, 35-acre (14 ha) campus in Midpoint Technology Park intended for staff offices; development was delayed by The Great Recession. In 2015 the university announced a development plan and the Redwood City campus opened in March 2019.

The Bass Center in Washington, DC provides a base, including housing, for the Stanford in Washington program for undergraduates. It includes a small art gallery open to the public.

China: Stanford Center at Peking University, housed in the Lee Jung Sen Building, is a small center for researchers and students in collaboration with Beijing University [北京大学](CN) (Kavli Institute for Astronomy and Astrophysics at Peking University(CN) (KIAA-PKU).

Administration and organization

Stanford is a private, non-profit university that is administered as a corporate trust governed by a privately appointed board of trustees with a maximum membership of 38. Trustees serve five-year terms (not more than two consecutive terms) and meet five times annually.[83] A new trustee is chosen by the current trustees by ballot. The Stanford trustees also oversee the Stanford Research Park, the Stanford Shopping Center, the Cantor Center for Visual Arts, Stanford University Medical Center, and many associated medical facilities (including the Lucile Packard Children’s Hospital).

The board appoints a president to serve as the chief executive officer of the university, to prescribe the duties of professors and course of study, to manage financial and business affairs, and to appoint nine vice presidents. The provost is the chief academic and budget officer, to whom the deans of each of the seven schools report. Persis Drell became the 13th provost in February 2017.

As of 2018, the university was organized into seven academic schools. The schools of Humanities and Sciences (27 departments), Engineering (nine departments), and Earth, Energy & Environmental Sciences (four departments) have both graduate and undergraduate programs while the Schools of Law, Medicine, Education and Business have graduate programs only. The powers and authority of the faculty are vested in the Academic Council, which is made up of tenure and non-tenure line faculty, research faculty, senior fellows in some policy centers and institutes, the president of the university, and some other academic administrators, but most matters are handled by the Faculty Senate, made up of 55 elected representatives of the faculty.

The Associated Students of Stanford University (ASSU) is the student government for Stanford and all registered students are members. Its elected leadership consists of the Undergraduate Senate elected by the undergraduate students, the Graduate Student Council elected by the graduate students, and the President and Vice President elected as a ticket by the entire student body.

Stanford is the beneficiary of a special clause in the California Constitution, which explicitly exempts Stanford property from taxation so long as the property is used for educational purposes.

Endowment and donations

The university’s endowment, managed by the Stanford Management Company, was valued at $27.7 billion as of August 31, 2019. Payouts from the Stanford endowment covered approximately 21.8% of university expenses in the 2019 fiscal year. In the 2018 NACUBO-TIAA survey of colleges and universities in the United States and Canada, only Harvard University(US), the University of Texas System(US), and Yale University(US) had larger endowments than Stanford.

In 2006, President John L. Hennessy launched a five-year campaign called the Stanford Challenge, which reached its $4.3 billion fundraising goal in 2009, two years ahead of time, but continued fundraising for the duration of the campaign. It concluded on December 31, 2011, having raised a total of $6.23 billion and breaking the previous campaign fundraising record of $3.88 billion held by Yale. Specifically, the campaign raised $253.7 million for undergraduate financial aid, as well as $2.33 billion for its initiative in “Seeking Solutions” to global problems, $1.61 billion for “Educating Leaders” by improving K-12 education, and $2.11 billion for “Foundation of Excellence” aimed at providing academic support for Stanford students and faculty. Funds supported 366 new fellowships for graduate students, 139 new endowed chairs for faculty, and 38 new or renovated buildings. The new funding also enabled the construction of a facility for stem cell research; a new campus for the business school; an expansion of the law school; a new Engineering Quad; a new art and art history building; an on-campus concert hall; a new art museum; and a planned expansion of the medical school, among other things. In 2012, the university raised $1.035 billion, becoming the first school to raise more than a billion dollars in a year.

Research centers and institutes

DOE’s SLAC National Accelerator Laboratory(US)
Stanford Research Institute, a center of innovation to support economic development in the region.
Hoover Institution, a conservative American public policy institution and research institution that promotes personal and economic liberty, free enterprise, and limited government.
Hasso Plattner Institute of Design, a multidisciplinary design school in cooperation with the Hasso Plattner Institute of University of Potsdam [Universität Potsdam](DE) that integrates product design, engineering, and business management education).
Martin Luther King Jr. Research and Education Institute, which grew out of and still contains the Martin Luther King Jr. Papers Project.
John S. Knight Fellowship for Professional Journalists
Center for Ocean Solutions
Together with UC Berkeley(US) and UC San Francisco(US), Stanford is part of the Biohub, a new medical science research center founded in 2016 by a $600 million commitment from Facebook CEO and founder Mark Zuckerberg and pediatrician Priscilla Chan.

Discoveries and innovation

Natural sciences

Biological synthesis of deoxyribonucleic acid (DNA) – Arthur Kornberg synthesized DNA material and won the Nobel Prize in Physiology or Medicine 1959 for his work at Stanford.
First Transgenic organism – Stanley Cohen and Herbert Boyer were the first scientists to transplant genes from one living organism to another, a fundamental discovery for genetic engineering. Thousands of products have been developed on the basis of their work, including human growth hormone and hepatitis B vaccine.
Laser – Arthur Leonard Schawlow shared the 1981 Nobel Prize in Physics with Nicolaas Bloembergen and Kai Siegbahn for his work on lasers.
Nuclear magnetic resonance – Felix Bloch developed new methods for nuclear magnetic precision measurements, which are the underlying principles of the MRI.

Computer and applied sciences

ARPANETStanford Research Institute, formerly part of Stanford but on a separate campus, was the site of one of the four original ARPANET nodes.

Internet—Stanford was the site where the original design of the Internet was undertaken. Vint Cerf led a research group to elaborate the design of the Transmission Control Protocol (TCP/IP) that he originally co-created with Robert E. Kahn (Bob Kahn) in 1973 and which formed the basis for the architecture of the Internet.

Frequency modulation synthesis – John Chowning of the Music department invented the FM music synthesis algorithm in 1967, and Stanford later licensed it to Yamaha Corporation.

Google – Google began in January 1996 as a research project by Larry Page and Sergey Brin when they were both PhD students at Stanford. They were working on the Stanford Digital Library Project (SDLP). The SDLP’s goal was “to develop the enabling technologies for a single, integrated and universal digital library” and it was funded through the National Science Foundation, among other federal agencies.

Klystron tube – invented by the brothers Russell and Sigurd Varian at Stanford. Their prototype was completed and demonstrated successfully on August 30, 1937. Upon publication in 1939, news of the klystron immediately influenced the work of U.S. and UK researchers working on radar equipment.

RISCARPA funded VLSI project of microprocessor design. Stanford and UC Berkeley are most associated with the popularization of this concept. The Stanford MIPS would go on to be commercialized as the successful MIPS architecture, while Berkeley RISC gave its name to the entire concept, commercialized as the SPARC. Another success from this era were IBM’s efforts that eventually led to the IBM POWER instruction set architecture, PowerPC, and Power ISA. As these projects matured, a wide variety of similar designs flourished in the late 1980s and especially the early 1990s, representing a major force in the Unix workstation market as well as embedded processors in laser printers, routers and similar products.
SUN workstation – Andy Bechtolsheim designed the SUN workstation for the Stanford University Network communications project as a personal CAD workstation, which led to Sun Microsystems.

Businesses and entrepreneurship

Stanford is one of the most successful universities in creating companies and licensing its inventions to existing companies; it is often held up as a model for technology transfer. Stanford’s Office of Technology Licensing is responsible for commercializing university research, intellectual property, and university-developed projects.

The university is described as having a strong venture culture in which students are encouraged, and often funded, to launch their own companies.

Companies founded by Stanford alumni generate more than $2.7 trillion in annual revenue, equivalent to the 10th-largest economy in the world.

Some companies closely associated with Stanford and their connections include:

Hewlett-Packard, 1939, co-founders William R. Hewlett (B.S, PhD) and David Packard (M.S).
Silicon Graphics, 1981, co-founders James H. Clark (Associate Professor) and several of his grad students.
Sun Microsystems, 1982, co-founders Vinod Khosla (M.B.A), Andy Bechtolsheim (PhD) and Scott McNealy (M.B.A).
Cisco, 1984, founders Leonard Bosack (M.S) and Sandy Lerner (M.S) who were in charge of Stanford Computer Science and Graduate School of Business computer operations groups respectively when the hardware was developed.[163]
Yahoo!, 1994, co-founders Jerry Yang (B.S, M.S) and David Filo (M.S).
Google, 1998, co-founders Larry Page (M.S) and Sergey Brin (M.S).
LinkedIn, 2002, co-founders Reid Hoffman (B.S), Konstantin Guericke (B.S, M.S), Eric Lee (B.S), and Alan Liu (B.S).
Instagram, 2010, co-founders Kevin Systrom (B.S) and Mike Krieger (B.S).
Snapchat, 2011, co-founders Evan Spiegel and Bobby Murphy (B.S).
Coursera, 2012, co-founders Andrew Ng (Associate Professor) and Daphne Koller (Professor, PhD).

Student body

Stanford enrolled 6,996 undergraduate and 10,253 graduate students as of the 2019–2020 school year. Women comprised 50.4% of undergraduates and 41.5% of graduate students. In the same academic year, the freshman retention rate was 99%.

Stanford awarded 1,819 undergraduate degrees, 2,393 master’s degrees, 770 doctoral degrees, and 3270 professional degrees in the 2018–2019 school year. The four-year graduation rate for the class of 2017 cohort was 72.9%, and the six-year rate was 94.4%. The relatively low four-year graduation rate is a function of the university’s coterminal degree (or “coterm”) program, which allows students to earn a master’s degree as a 1-to-2-year extension of their undergraduate program.

As of 2010, fifteen percent of undergraduates were first-generation students.

Athletics

As of 2016 Stanford had 16 male varsity sports and 20 female varsity sports, 19 club sports and about 27 intramural sports. In 1930, following a unanimous vote by the Executive Committee for the Associated Students, the athletic department adopted the mascot “Indian.” The Indian symbol and name were dropped by President Richard Lyman in 1972, after objections from Native American students and a vote by the student senate. The sports teams are now officially referred to as the “Stanford Cardinal,” referring to the deep red color, not the cardinal bird. Stanford is a member of the Pac-12 Conference in most sports, the Mountain Pacific Sports Federation in several other sports, and the America East Conference in field hockey with the participation in the inter-collegiate NCAA’s Division I FBS.

Its traditional sports rival is the University of California, Berkeley, the neighbor to the north in the East Bay. The winner of the annual “Big Game” between the Cal and Cardinal football teams gains custody of the Stanford Axe.

Stanford has had at least one NCAA team champion every year since the 1976–77 school year and has earned 126 NCAA national team titles since its establishment, the most among universities, and Stanford has won 522 individual national championships, the most by any university. Stanford has won the award for the top-ranked Division 1 athletic program—the NACDA Directors’ Cup, formerly known as the Sears Cup—annually for the past twenty-four straight years. Stanford athletes have won medals in every Olympic Games since 1912, winning 270 Olympic medals total, 139 of them gold. In the 2008 Summer Olympics, and 2016 Summer Olympics, Stanford won more Olympic medals than any other university in the United States. Stanford athletes won 16 medals at the 2012 Summer Olympics (12 gold, two silver and two bronze), and 27 medals at the 2016 Summer Olympics.

Traditions

The unofficial motto of Stanford, selected by President Jordan, is Die Luft der Freiheit weht. Translated from the German language, this quotation from Ulrich von Hutten means, “The wind of freedom blows.” The motto was controversial during World War I, when anything in German was suspect; at that time the university disavowed that this motto was official.
Hail, Stanford, Hail! is the Stanford Hymn sometimes sung at ceremonies or adapted by the various University singing groups. It was written in 1892 by mechanical engineering professor Albert W. Smith and his wife, Mary Roberts Smith (in 1896 she earned the first Stanford doctorate in Economics and later became associate professor of Sociology), but was not officially adopted until after a performance on campus in March 1902 by the Mormon Tabernacle Choir.
“Uncommon Man/Uncommon Woman”: Stanford does not award honorary degrees, but in 1953 the degree of “Uncommon Man/Uncommon Woman” was created to recognize individuals who give rare and extraordinary service to the University. Technically, this degree is awarded by the Stanford Associates, a voluntary group that is part of the university’s alumni association. As Stanford’s highest honor, it is not conferred at prescribed intervals, but only when appropriate to recognize extraordinary service. Recipients include Herbert Hoover, Bill Hewlett, Dave Packard, Lucile Packard, and John Gardner.
Big Game events: The events in the week leading up to the Big Game vs. UC Berkeley, including Gaieties (a musical written, composed, produced, and performed by the students of Ram’s Head Theatrical Society).
“Viennese Ball”: a formal ball with waltzes that was initially started in the 1970s by students returning from the now-closed Stanford in Vienna overseas program. It is now open to all students.
“Full Moon on the Quad”: An annual event at Main Quad, where students gather to kiss one another starting at midnight. Typically organized by the Junior class cabinet, the festivities include live entertainment, such as music and dance performances.
“Band Run”: An annual festivity at the beginning of the school year, where the band picks up freshmen from dorms across campus while stopping to perform at each location, culminating in a finale performance at Main Quad.
“Mausoleum Party”: An annual Halloween Party at the Stanford Mausoleum, the final resting place of Leland Stanford Jr. and his parents. A 20-year tradition, the “Mausoleum Party” was on hiatus from 2002 to 2005 due to a lack of funding, but was revived in 2006. In 2008, it was hosted in Old Union rather than at the actual Mausoleum, because rain prohibited generators from being rented. In 2009, after fundraising efforts by the Junior Class Presidents and the ASSU Executive, the event was able to return to the Mausoleum despite facing budget cuts earlier in the year.
Former campus traditions include the “Big Game bonfire” on Lake Lagunita (a seasonal lake usually dry in the fall), which was formally ended in 1997 because of the presence of endangered salamanders in the lake bed.

Award laureates and scholars

Stanford’s current community of scholars includes:

19 Nobel Prize laureates (as of October 2020, 85 affiliates in total)
171 members of the National Academy of Sciences
109 members of National Academy of Engineering
76 members of National Academy of Medicine
288 members of the American Academy of Arts and Sciences
19 recipients of the National Medal of Science
1 recipient of the National Medal of Technology
4 recipients of the National Humanities Medal
49 members of American Philosophical Society
56 fellows of the American Physics Society (since 1995)
4 Pulitzer Prize winners
31 MacArthur Fellows
4 Wolf Foundation Prize winners
2 ACL Lifetime Achievement Award winners
14 AAAI fellows
2 Presidential Medal of Freedom winners

Stanford University Seal