Energy exchange between phononic and electronic subsystems governing the nonlinear conduction inDCNQI2Cu

Abstract

We present a dynamical study on the nonlinear conduction behaviour in the commensurate charge-density-wave phase of the quasi-one-dimensional conductor DCNQI 2 Cu below 75 K. We can accurately simulate magnitude and time-dependence of the measured conductivity in response to large voltage pulses by accounting for the energy exchange between the phononic and electronic subsystems by means of an electrothermal model. Our simulations reveal a distinct non-equilibrium population of optical phonon states with an average energy of E ph = 19 meV being half the activation energy of about ∆E a = 39 meV observed in DC resistivity measurements. By inelastic scattering, this hot optical phonon bath generates additional charge-carrying excitations thus providing a multiplication effect while energy transferred to the acoustic phonons is dissipated out of the system via heat conduction. Therefore, in high electric fields a preferred interaction of chargecarrying excitations with optical phonons compared to acoustic phonon modes is considered to be responsible for the nonlinear conduction effects observed in DCNQI 2 Cu.

Momentum-Resolved View of Electron-Phonon Coupling in Multilayer WSe2

“…Whereas macroscopic heat and electrical transport properties can be measured directly, the observation of the underlying microscopic processes, i.e., the scattering processes of carriers and of phonons, requires methods with time, momentum, and energy resolution to be understood in detail. Such information can be decisive in the correct determination of transport properties [8,9] or energy relaxation [10][11][12]. A momentum-resolved view of scattering processes will in addition be of uttermost importance in conceiving novel quantum technologies harnessing spin and valley degrees of freedom [13][14][15], as they utilize carrier populations at specific positions in momentum space.…”