Electronic Bloch oscillation in bilayer graphene gradient superlattices

TL;DR

This paper demonstrates that electronic Bloch oscillations up to terahertz frequencies can be induced in bilayer graphene superlattices with gradient potentials, revealing potential for high-frequency electronic applications.

Contribution

It introduces a method to induce and analyze Bloch oscillations in bilayer graphene superlattices with gradient potentials, showing their frequency tunability and associated wave localization effects.

Findings

Bloch oscillations up to terahertz frequencies observed.

Wannier-Stark ladders identified as equidistant transmission peaks.

Oscillation period decreases linearly with potential gradient.

Abstract

We investigate the electronic Bloch oscillation in bilayer graphene gradient superlattices using transfer matrix method. By introducing two kinds of gradient potentials of square barriers along electrons propagation direction, we find that Bloch oscillations up to terahertz can occur. Wannier-Stark ladders, as the counterpart of Bloch oscillation, are obtained as a series of equidistant transmission peaks, and the localization of the electronic wave function is also signature of Bloch oscillation. Forthermore, the period of Bloch oscillation decreases linearly with increasing gradient of barrier potentials.