Photogalvanic transport in fluctuating Ising superconductors

Abstract

In a two-dimensional noncentrosymmetric Ising superconductor in a fluctuating regime under the action of a uniform external electromagnetic field, there emerge two contributions to the photogalvanic effect due to the trigonal warping of the valleys. The first contribution stems from the current of the electron gas in its normal state, while the second contribution is of an Aslamazov-Larkin nature: It originates from the presence of fluctuating Cooper pairs when the ambient temperature approaches (from above) the temperature of the superconducting transition in the sample. The way to lift the valley degeneracy is the application of a weak out-of-plane external magnetic field producing a Zeeman effect. The Boltzmann equations' approach for the electron gas in the normal state and the time-dependent Ginzburg-Landau equations for the fluctuating Cooper pairs allow for the study of the photogalvanic current in two-dimensional transition-metal dichalcogenide Ising superconductors.