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    Probing Deep Into the Very Nature of Electrons With the World’s Purest Sample of Gallium Arsenide

    Princeton researchers have created the world’s purest sample of gallium arsenide, a semiconductor used in specialized systems such as satellites. This photo shows a sample wired inside an experimental device that sees electrons in a two-dimensional plane. The purity of the sample revealed a strange effect under a relatively weak magnetic field. This is an operation without an established theoretical framework.Credit: Researcher

    Princeton researchers have created the world’s purest sample of gallium arsenide, a semiconductor used in devices that power technologies such as mobile phones and satellites.

    The team burned the material into one impurity for every 10 billion atoms, reaching a quality level that surpassed even the world’s purest silicon sample used to validate a 1 kilogram standard. The finished gallium arsenide chip was a square about the same width as a pencil eraser, allowing the team to take a deeper look at the nature of the electrons themselves.

    Instead of sending the chip into space, researchers take ultra-high-purity samples beneath Princeton’s engineering rectangle, wire it there, freeze it to a lower temperature than space, and use a strong magnetic field. It transmits electrons through a two-dimensional plane sandwiched between the encapsulation, the voltage, and the crystal layer of the material. As they lowered the magnetic field, they discovered an amazing set of effects.

    Result is, Nature MaterialsShowed that many of today’s cutting-edge physics-promoting phenomena can be observed in much weaker magnetic fields than previously thought. Lower magnetic fields may empower more laboratories to study the mysterious physics problems buried in such two-dimensional systems. According to researchers, it’s more exciting. These less stringent conditions present physics without an established theoretical framework and pave the way for further investigation of quantum phenomena.

    One surprise occurred when the electrons were aligned to a lattice structure known as a Wigner crystal. Scientists previously thought that Wigner crystals require a very strong magnetic field of about 14 Tesla. “It’s strong enough to levitate frogs,” said Kevin Villegas Rosales, one of the first two authors of the study, who recently received his PhD. Electrical and computer engineering. However, this study showed that electrons can crystallize in less than one tesla. “We needed super high quality to see them,” he said.

    The team also observed that the “vibration” of the electrical resistance of the system increased by about 80%, and the “activation gap” of what was called the fractional quantum Hall effect, which is an important topic in condensed matter physics and quantum computation, increased. bottom. The fractional quantum Hall effect was first discovered by Princeton University’s Arthur Legrand Dotty, Professor of Electrical and Computer Engineering, and Professor Emeritus Daniel C. Tsui. Daniel C. Tsui won the Nobel Prize in Physics for his discovery.

    The study was put together as part of an ongoing collaborative effort between Principal Investigator Mansour Shayegan, a professor of electrical and computer engineering, and Senior ECE researcher Loren Pfeiffer.

    “There was a great relationship between our labs,” Shayegan said. About 10 years ago, he and Pfeiffer, then working at Bell Labs, continued to compete friendly for purer materials that would enable them to study more interesting physics problems than ever before. After that, Pfeiffer joined Princeton.

    As colleagues in the same department, they were free to combine forces and are no longer trying to best each other. They quickly developed a natural divide-and-conquer for the questions they were previously trying to answer. Over the next decade or more, Pfeiffer’s group has built one of the world’s finest material depositors, and Shagan’s group is at the forefront of studying the physics revealed by these ultra-purity materials. I refined the method.

    See also: Yoon Jang Chung, KA Villegas Rosales, KW Baldwin, PT Madathil, KW West, M. “Ultra High Quality 2D Electronic System” by Shayegan, LN Pfeiffer, February 25, 2021 Nature Materials..
    DOI: 10.1038 / s41563-021-00942-3

    In addition to working together, these two researchers provide co-advice to many graduate students working in the lab, including Villegas Rosales and Edwin Chung, the other lead author of the dissertation. Chung also got a PhD. This year, I am a postdoctoral researcher in the same two groups. Villegas Rosales has joined Quantum Machines. Quantum computing A start-up company as an engineer.

    The paper “Ultra High Quality Two-Dimensional Electronic Systems” published in Nature Materials on February 25, 2021 was supported by grants from the National Science Foundation, the Gordon and Betty Moore Foundation, and the US Department of Energy. Additional authors include graduate student Pranav Madathil and senior Princeton researchers Kirk W. Baldwin and KW West.

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    Probing Deep Into the Very Nature of Electrons With the World’s Purest Sample of Gallium Arsenide Source link Probing Deep Into the Very Nature of Electrons With the World’s Purest Sample of Gallium Arsenide

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