Light-modulated anisotropic Andreev reflection across an 8-Pmmn borophene-based superconducting junction

Abstract

We investigate the Andreev reflection across an 8-Pmmn borophene-based superconducting junction irradiated by the linearly polarized off-resonant light with the polarization along x and y directions, respectively. In the regime of the interband conversion of electron–hole, Andreev retro-reflection happens in both cases of the polarization along x and y directions except perpendicular direction of junction. In the regime of the intraband conversion of electron–hole, specular Andreev reflection happens regardless of the directions of polarization except perpendicular direction of junction. In both regimes of the conversion of electron–hole, the values of differential conductance are different in the different directions of junction and different directions of polarization, i.e., an anisotropic conductance is generated. In addition, the nonzero incident angle of the perfect Andreev reflection can be tuned by adjusting the directions of junction and polarization. All these properties of Andreev reflection arise from the light-modulated anisotropic band structure of borophene.