Geometric Photon-Drag Effect and Nonlinear Shift Current in Centrosymmetric Crystals.

Li-Kun Shi,Kai Chang,Dong Zhang,Justin C W Song

doi:10.1103/physrevlett.126.197402

Abstract

The nonlinear shift current, also known as the bulk photovoltaic current generated by linearly polarized light, has long been known to be absent in crystals with inversion symmetry. Here we argue that a nonzero shift current in centrosymmetric crystals can be activated by a photon-drag effect. Photon-drag shift current proceeds from a "shift current dipole" (a geometric quantity characterizing interband transitions) and manifests a purely transverse response in centrosymmetric crystals. This transverse nature proceeds directly from the shift-vector's pseudovector nature under mirror operation and underscores its intrinsic geometric origin. Photon-drag shift current can be greatly enhanced by coupling to polaritons and provides a new and sensitive tool to interrogate the subtle interband coherences of materials with inversion symmetry previously thought to be inaccessible via photocurrent probes.

Highlights

The nonlinear shift current, known as the bulk photovoltaic current generated by linearly polarized light, has long been known to be absent in crystals with inversion symmetry
Photon-drag shift current can be greatly enhanced by coupling to polaritons and provides a new and sensitive tool to interrogate the subtle interband coherences of materials with inversion symmetry previously thought to be inaccessible via photocurrent probes
While such geometric phases can be found in a large variety of materials, since photocurrent is a vector, broken symmetries are required in fixing the direction of shift current in a uniform bulk

Summary

Introduction

The nonlinear shift current, known as the bulk photovoltaic current generated by linearly polarized light, has long been known to be absent in crystals with inversion symmetry. Geometric Photon-Drag Effect and Nonlinear Shift Current in Centrosymmetric Crystals We argue that a nonzero shift current in centrosymmetric crystals can be activated by a photon-drag effect.

Results

Conclusion