Layer photovoltaic effect in van der Waals heterostructures

TL;DR

This paper introduces the layer photovoltaic effect (LPE) in van der Waals heterostructures, demonstrating how light can control layer polarization with potential applications in terahertz photodetection.

Contribution

It systematically classifies the mechanisms of LPE and explores its dependence on symmetry and light polarization in layered heterostructures.

Findings

LPE can be induced by various light polarizations, including unpolarized light.

Layer polarization susceptibilities are significant in the terahertz frequency range.

LPE offers a new approach for bulk photodetection in layered materials.

Abstract

We argue that the layer electric polarization of noncentrosymmetric layered heterostructures can be generically controlled by light yielding a layer photovoltaic effect (LPE). The LPE possesses a rich phenomenology and can arise from myriad distinct mechanisms displaying strong sensitivity to symmetry (e.g., point group and time-reversal) as well as the presence/absence of a Fermi surface. We systematically classify these and unveil how LPE manifests for a range of light polarizations and even for unpolarized light. These unusual layer photoresponses can be realized in a range of layered heterostructures such as bilayer graphene aligned on hexagonal Boron Nitride and manifest sizeable layer polarization susceptibilities in the terahertz frequency range that can be used as novel means of bulk photodetection.