Phys.org February 12, 2024 Understanding electron-phonon interactions is fundamentally important and has crucial implications for device applications. However, in twisted bilayer graphene near the magic angle, this understanding is currently lacking. An international team of researchers (Spain, Japan, USA – MIT, Germany) studied electron-phonon coupling using time- and frequency-resolved photovoltage measurements as direct and complementary probes of phonon-mediated hot-electron cooling. They found a remarkable speedup in cooling of twisted bilayer graphene near the magic angle: the cooling time was a few picoseconds from room temperature down to 5 kelvin, whereas in pristine bilayer graphene, cooling to phonons becomes much slower […]
Tag Archives: Electron-Phonon interaction
Newly observed phenomenon could lead to new quantum devices
MIT News June 15, 2020 Kohn anomalies reflect a sudden change in the graph describing a change of the capability of electrons for shielding phonons. This can give rise to instabilities in the propagation of electrons through the material and can lead to many new electronic properties. A team of researchers in the US (MIT, Pennsylvania State University, Argonne National Laboratory, Oak Ridge National Laboratory, NIST, University of Maryland) predicted and observed Kohn anomaly in the topological Weyl semimetal (WSM) tantalum phosphide. It exhibits multiple topological singularities of Weyl nodes, leading to a distinct nesting condition with chiral selection, a […]