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 […]