Ballistic Electronic Transport through an Oscillating Barrier in Graphene

Abstract

Graphene is one of the prospective materials for usage in new electronic devices. Its various properties and potential appli- cations are still under large-scale studies. One of the active re- search areas is oriented towards development of a graphene-based transistor which technical characteristics would top the current Si-based designs. This thesis concentrates on a scattering prob- lem in one of such devices driven with static and time-periodic external voltages. Electrical conductance through a four-terminal graphene de- vice is examined from a quantum-mechanical point of view. A high static barrier scattering problem is solved and demonstrated to be in agreement with previous results. Differences between graphene-based and Schro ̈dinger-type systems are highlighted. Time-dependent transport is studied. Formation of energy sidebands and their relation to driving parameters is examined in details. Corrections to the static conductance are obtained for AC perturbation to static potential. Formation of bound states is investigated in the framework of first-order perturbation theory, adiabatic limit is presented. Noise calculation is presented for the static-driving case. Re- sults for zero-frequency noise and Fano factor are obtained and compared to graphene-based systems with different layouts.