Coherent modulation of the electron temperature and electron–phonon couplings in a 2D material

Abstract

Significance The interactions between electrons and lattice vibrations called phonons not only determine the properties of materials, but also give rise to remarkable phenomena such as superconductivity or spatial ordering of the charges and lattice. Here, we use a femtosecond laser to excite and spatially relocate electrons in TaSe 2 . In all observations to date, these excited electrons cool monotonically by scattering with phonons. Surprisingly, we observe an oscillation of the electron temperature that is coupled with the lattice breathing mode, and a switching in the dominant electron–phonon interactions by varying the laser excitation. Our results demonstrate a promising way to manipulate electron–phonon interactions, opening up routes to steer a quantum material toward a desired state using light.