
Nanotechnology Now – Press Release: Semiconductor lattice marrying electrons and magnetic moments
Home > Pressurization > Semiconductor lattice couples electrons and magnetic moments
Yu-Tsun Shao and David Muller/Provided Transmission electron microscopy image showing molybdenum ditelluride and tungsten selenide lattices. |
Abstract:
A model system created by stacking pairs of monolayer semiconductors provides physicists with a simpler way to study the behavior of quantum disruptors, from heavy fermions to exotic quantum phase transitions.
Semiconductor lattice couples electrons and magnetic moments
Ithaca, New York | Posted on March 24, 2023
The group’s paper, Gate-Tunable Heavy Fermions in Moir Kondo Lattice, was published March 15 in Nature. The lead author is postdoctoral fellow Wenjin Zhao at the Kavli Institute at Cornell.
The project was led by Kin Fai Mak, professor of physics at the College of Arts and Sciences, and Jie Shan, professor of applied physics and engineering at Cornell Engineering and at A&S, the paper’s senior co-author. The two researchers are members of the Kavli Institute; they came to Cornell through the provost’s Nanoscale Science and Microsystems Engineering (NEXT Nano) initiative.
The team set out to overcome what is known as the Kondo effect, named after Japanese theoretical physicist Jun Kondo. About six decades ago, experimental physicists discovered that by taking a metal and replacing even a small number of atoms with magnetic impurities, they could scatter the material’s conduction electrons and radically change its resistivity.
The phenomenon baffled physicists, but Kondo explained it with a model showing how conduction electrons can filter out magnetic impurities, so that the electron spins pair with the magnetic impurity spins in the opposite direction, forming a singlet.
While the Kondo impurity problem is now well understood, the Kondo lattice problem with regular lattice magnetic moments instead of random magnetic impurities is far more complicated and continues to baffle physicists. Experimental studies of the Kondo lattice problem usually involve intermetallic compounds of rare earth elements, but these materials have their own limitations.
As you move down the Periodic Table, you end up with about 70 electrons in an atom, Mak said. The electronic structure of the material becomes very complicated. It’s really hard to describe what happened even without Kondo’s interaction.
The researchers simulated the Kondo lattice by stacking ultrathin monolayers of two semiconductors: molybdenum ditelluride, tuned to the Mott insulating state, and tungsten selenide, doped with roving conduction electrons. These materials are much simpler than the bulky intermetallic compounds, and stacked with a clever twist. By rotating the layers at an angle of 180 degrees, their overlap produces a moir lattice pattern that traps individual electrons in tiny slots, similar to an egg in an egg carton.
This configuration avoids the hassle of dozens of electrons jumbling together in the rare earth elements. And instead of requiring chemistry to prepare the usual magnetic moment arrays in intermetallic compounds, the simplified Kondo lattice requires only a battery. When the voltage is applied just right, the material is ordered to form a lattice of spins, and when one cranks to a different voltage, the spins are turned off, resulting in a continuously tunable system.
Everything became simpler and more controllable, says Mak.
The researchers were able to continuously tune the electron mass and spin density, which is not possible in conventional materials, and in the process they observed that electrons coated with a spin lattice could be 10 to 20 times heavier than naked electrons. , depending on the applied voltage.
Tunability can also induce quantum phase transitions in which heavy electrons change to light electrons with, among other things, the possibility of appearance of odd metallic phases, in which the electrical resistance increases linearly with temperature. Realization of this type of transition could be very useful for understanding the phenomenology of high-temperature superconductors in copper oxide.
Our results can provide laboratory benchmarks for theorists, said Mak. In condensed matter physics, theorists try to deal with the complex problem of one trillion interacting electrons. It would be nice if they didn’t have to worry about other complications, like chemistry and materials science, in real materials. So they often study these materials with the spherical shape of the Kondo cow lattice model. In the real world you can’t make a round cow, but in our materials we have now made one for the Kondo grid.
Co-authors include doctoral students Bowen Shen and Zui Tao; postdoctoral researchers Kaifei Kang and Zhongdong Han; and researchers from the National Institute for Materials Science in Tsukuba, Japan.
This research was primarily supported by the Air Force Office of Scientific Research, the National Science Foundation, the US Department of Energy, and the Gordon and Betty Moore Foundation.
####
For more information, please click Here
Contact:
Beck Bowyer
Cornell University
Office: 607-220-4185
Copyright © Cornell University
If you have any comments, please Contact us.
The news release publisher, not 7th Wave, Inc. or Nanotechnology Now, is solely responsible for the accuracy of the content.
Quantum physics
New experiment translating quantum information between technologies in important step for quantum internet March 24, 2023
News and information
Optical switching at record speed opens the door to light-based ultrafast electronics and computers: March 24, 2023
Robotic caterpillars demonstrate a new approach to locomotion for soft robotics March 24, 2023
Light meets deep learning: computing fast enough for the next generation of AI March 24, 2023
Solid polymer electrolyte reinforced bilayer PET/PVDF substrate enhances solid state lithium metal battery performance March 24, 2023
Government-Legislation/Regulation/Funding/Policy
New experiment translating quantum information between technologies in important step for quantum internet March 24, 2023
Optical switching at record speed opens the door to light-based ultrafast electronics and computers: March 24, 2023
Robotic caterpillars demonstrate a new approach to locomotion for soft robotics March 24, 2023
Stanford researchers develop new way to identify bacteria in fluids: Innovative adaptation of technology in old inkjet printers plus AI-assisted imaging yields a faster, cheaper way to find bacteria in blood, wastewater and more March 3, 2023
Possible Futures
New experiment translating quantum information between technologies in important step for quantum internet March 24, 2023
Graphene is growing and we can see it March 24, 2023
HKUMed creates new two-dimensional (2D) ultrasonography-responsive antibacterial nanosheets to effectively treat bone tissue infections March 24, 2023
Universal HCl assistant powder-to-powder strategy for preparing lead-free perovskites March 24, 2023
Chip Technology
Graphene is growing and we can see it March 24, 2023
Optical switching at record speed opens the door to light-based ultrafast electronics and computers: March 24, 2023
Light meets deep learning: computing fast enough for the next generation of AI March 24, 2023
Researchers develop innovative tools to measure electron dynamics in semiconductors: Insights can lead to more energy-efficient chips and electronic devices March 3, 2023
Invention
New experiment translating quantum information between technologies in important step for quantum internet March 24, 2023
Graphene is growing and we can see it March 24, 2023
HKUMed creates new two-dimensional (2D) ultrasonography-responsive antibacterial nanosheets to effectively treat bone tissue infections March 24, 2023
Universal HCl assistant powder-to-powder strategy for preparing lead-free perovskites March 24, 2023
Announcement
Robotic caterpillars demonstrate a new approach to locomotion for soft robotics March 24, 2023
Light meets deep learning: computing fast enough for the next generation of AI March 24, 2023
Solid polymer electrolyte reinforced bilayer PET/PVDF substrate enhances solid state lithium metal battery performance March 24, 2023
Understanding the mechanism of non-uniform diamond film formation on tools: Paving the way to a dry process with less environmental impact 24 March 2023
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White Papers/Posters
HKUMed creates new two-dimensional (2D) ultrasonography-responsive antibacterial nanosheets to effectively treat bone tissue infections March 24, 2023
Universal HCl assistant powder-to-powder strategy for preparing lead-free perovskites March 24, 2023
Optical switching at record speed opens the door to light-based ultrafast electronics and computers: March 24, 2023
Robotic caterpillars demonstrate a new approach to locomotion for soft robotics March 24, 2023
Military
New experiment translating quantum information between technologies in important step for quantum internet March 24, 2023
Optical switching at record speed opens the door to light-based ultrafast electronics and computers: March 24, 2023
Scientists increase quantum signal while reducing noise: Squeezing noise through a wide frequency bandwidth in quantum systems can lead to faster and more accurate quantum measurements February 10, 2023
Make them thin enough, and the antiferroelectric material becomes ferroelectric February 10, 2023
Grants/Sponsored Research/Awards/Scholarships/Prizes/Contests/Awards/Records
Optical switching at record speed opens the door to light-based ultrafast electronics and computers: March 24, 2023
Stanford researchers develop new way to identify bacteria in fluids: Innovative adaptation of technology in old inkjet printers plus AI-assisted imaging yields a faster, cheaper way to find bacteria in blood, wastewater and more March 3, 2023
UCF researcher accepts Samsung International Global Research Outreach Award: Award from multinational electronics company to fund development of infrared night vision and thermal sensing camera technology for mobile phones and consumer electronics January 27, 2023
UC Irvine researchers decipher atomic-scale imperfections in lithium-ion batteries: Team uses super-high-resolution microscope enhanced with deep machine learning January 27, 2023
quantum nanoscience
Shattering superconductivity in kagome metals: Electronic control of quantum transitions in candidate materials for future low-energy electronics March 3, 2023
New study opens the door to ultrafast 2D devices that use nonequilibrium exciton superdiffusion February 10th, 2023
Scientists increase quantum signal while reducing noise: Squeezing noise through a wide frequency bandwidth in quantum systems can lead to faster and more accurate quantum measurements February 10, 2023
Danish quantum physicist makes a very important nanoscopic advance January 27, 2023