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 coupling
Thanks to trapped electrons, a material expected to be a conducting metal remains an insulator
Nanowerk July 13, 2023 Doped antiferromagnets host a vast array of physical properties and learning how to control them is one of the biggest challenges of condensed matter physics. La1.67Sr0.33NiO4 (LSNO) is a classic example of such a material. At low temperatures holes introduced via substitution of La by Sr segregate into lines to form boundaries between magnetically ordered domains in the form of stripes. The stripes become dynamic at high temperatures, but LSNO remains insulating presumably because an interplay between magnetic correlations and electron–phonon coupling localizes charge carriers. Magnetic degrees of freedom have been extensively investigated in this system, […]