Light-induced Andreev phase coherence and tunneling Hall effect in semi-Dirac systems

TL;DR

This paper theoretically demonstrates how off-resonant circularly polarized light induces phase coherence in semi-Dirac systems, leading to a tunneling Hall effect through asymmetric Andreev reflection, with potential applications in superconducting electronics.

Contribution

It introduces a phase-coherence mechanism for tunneling Hall currents in semi-Dirac superconducting junctions driven by light.

Findings

Light induces a phase for backreflected states depending on transverse momentum.

Transverse conductance reverses sign with light handedness.

Longitudinal conductance remains unaffected by light polarization.

Abstract

We theoretically investigate the charge transport in a normal metal/normal metal/superconductor junction based on semi-Dirac materials. It is shown that off-resonant circularly polarized light applied to the central normal region induces an additional phase for the backreflected states. This light-induced phase depends on the electron's transverse momenta and becomes coherent via multiple reflections, leading to a transversely asymmetric Andreev reflection, which in turn produces a tunneling Hall effect. Both the longitudinal and transverse conductances are obtained within the nonequilibrium Green's function formalism. While the longitudinal conductance is insensitive to the light handedness and only acquires a finite phase shift with varying intensity, the transverse conductance reverses sign upon switching the handedness, indicating the reversal of the tunneling Hall current. Our results establish a phase-coherence mechanism for generating tunneling Hall currents in superconducting tunnel junctions, suggesting potential applications in superconducting electronics.