Effect of Klein tunneling on conductance and shot noise in ballistic graphene

TL;DR

This paper investigates how Klein tunneling influences conductance and shot noise in ballistic graphene, using a trapezoid potential model and comparing theoretical predictions with experimental data.

Contribution

It introduces an exact solution approach for Klein tunneling effects in graphene with a trapezoid potential, highlighting asymmetry related to gate voltage sign.

Findings

Klein tunneling affects conductance and shot noise in graphene.

Theoretical results agree with experimental observations of Klein tunneling.

Asymmetry in conductance linked to Klein tunneling versus over-barrier reflection.

Abstract

The conductance and the Fano factor in a graphene sheet in the ballistic regime are calculated. The electrostatic potential in the sheet is modeled by a trapezoid barrier, which allows to use the exact solution of the Dirac equation in a uniform electric field in the slope areas (the two lateral sides of the trapezoid). A special attention is devoted to asymmetry with respect to the sign of the gate voltage, which is connected with the difference between the Klein tunneling and the over-barrier reflection. The comparison of the developed theory with the experiment supports the conclusion that the Klein tunneling was revealed experimentally.