Vertex corrections to nonlinear photoinduced currents in 2D superconductors
Abstract
The emergence of a rectified steady-state supercurrent as a response to the photoexcited current of the quasiparticles constitutes the concept of a superconducting photodiode. This phenomenon occurs in a two-dimensional thin superconducting film with a built-in DC supercurrent that is exposed to a circularly polarized external electromagnetic field. The flow of a Cooper-pair condensate, resulting as a second-order photo-response in a direction transverse to the initially built-in supercurrent, represents a superconducting counterpart to the photogalvanic effect. In this paper, we examine the photodiode supercurrent by restoring gauge invariance within the mean-field BCS framework. To achieve this, we derive an impurity-sensitive BCS-interaction-induced correction to the vertex function by performing self-consistent calculations within the Keldysh Green's function technique. The resulting photodiode current can be utilized for spectroscopic analysis of typical relaxation times in superconducting films.
Keywords
Cite
@article{arxiv.2506.17714,
title = {Vertex corrections to nonlinear photoinduced currents in 2D superconductors},
author = {A. V. Parafilo and V. M. Kovalev and I. G. Savenko},
journal= {arXiv preprint arXiv:2506.17714},
year = {2025}
}