Transport properties of vertical heterostructures under light irradiation

TL;DR

This paper investigates how light irradiation affects the electronic and transport properties of bilayer graphene and heterostructures, revealing gap openings and conductance modulation through theoretical modeling.

Contribution

It provides a theoretical analysis of light-induced modifications in transport properties of bilayer heterostructures using nonequilibrium Green's functions and tight-binding models.

Findings

Light induces sidebands and quasienergy gaps in the band structure.

Gaps lead to suppression of differential conductance.

Conductance can be enhanced near Van Hove singularities.

Abstract

Electronic and transport properties of bilayer heterostructure under light irradiation are of fundamental interest to improve functionality of optoelectronic devices. We theoretically study the modification of transport properties of bilayer graphene and bilayer heterostructures under a time-periodic external light field. The bulk electronic and transport properties are studied in a Landauer-type configuration by using the nonequilibrium Green's function formalism. To illustrate the behavior of the differential conductance of a bilayer contact under light illumination, we consider tight-binding models of bilayer graphene and graphene/hexagonal boron-nitride heterostructures. The non-adiabatic driving induces sidebands of the original band structure and opening of gaps in the quasienergy spectrum. In transport properties, the gap openings are manifested in a suppression of the differential conductance. In addition to suppression, an external light field induces an enhancement of the differential conductance if photoexcited electrons tunnel into or out of a Van~Hove singularity.