Transport through vertical graphene contacts under intense laser fields
Journal article, 2020

We theoretically study the electronic and transport properties of two graphene layers vertically coupled by an insulating layer under the influence of a time-periodic external light field. The nonadiabatic driving induces excitations of electrons and a redistribution of the occupied states which are manifested in the opening of gaps in the quasienergy spectrum of graphene. When a voltage is applied between the top and bottom graphene layers, the photoinduced nonequilibrium occupation modifies the transport properties of the contact. We investigate the electronic and transport properties of the contact by using the nonequilibrium Green's function formalism. To illustrate the behavior of the differential conductance of the vertical contact under light illumination, we consider two cases. First, we assume that both the bottom and top layers consist of graphene and, second, we consider a finite mass term in the bottom layer. We obtain that the differential conductance is strongly suppressed due to opening of gaps in the quasienergy spectrum in graphene. Additionally, the conductance shows features corresponding to the tunneling of photoexcited electrons at energies of the Van Hove singularity for both the top and bottom layers. In the case of a finite mass term in the bottom layer, the differential conductance can be directly related to the tunneling of photoexcited electrons.

Author

Pascal Stadler

Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics

Tomas Löfwander

Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics

Mikael Fogelström

Chalmers, Microtechnology and Nanoscience (MC2)

Physical Review Research

Vol. 2 023274

Areas of Advance

Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Materials Science

Subject Categories

Physical Sciences

Condensed Matter Physics

Roots

Basic sciences

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

DOI

10.1103/PhysRevResearch.2.023274

More information

Latest update

11/25/2020