The talk comprises of two parts. The first part is devoted to a theoretical description of nonlinear response, namely, the photogalvanic effect (PGE), in 2D superconductors based on transition mental dichalcogenide (TMD) monolayers in the vicinity of critical temperature of superconducting transition, Tc. The PGE transport is characterized by the stationary and uniform electric current as a second-order response to an external electromagnetic field. It turns out that superconducting fluctuations – emerging Cooper pairs before the system reaches the critical temperature – contribute to the PGE transport. This effect arises in the vicinity of Tc due to existing possibility of i) warping or ii) Rashba-type terms in the Cooper-pairs dispersion. Furthermore, we study the coherent PGE as a third-order response to external EM field in superconductors with isotropic dispersion of Cooper pairs.
At the end of the talk the effect of fluctuations to the plasmon resonance in 2D monolayers is briefly discussed.