Layer photovoltaic effect in van der Waals heterostructures

摘要: 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 (eg, 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. Strikingly, LPE manifests even for unpolarized light in rotationally symmetric heterostructures, sharply contrasting with that of in-plane photocurrent responses. These unusual layer photoresponses can be realized in a range of layered heterostructures such as bilayer graphene aligned on hexagonal boron nitride and manifest sizable layer polarization susceptibilities in the terahertz frequency range that can be used as a means of …