Berry Phase and Traversal Time in Asymmetric Graphene Structures

TL;DR

This paper investigates the Berry phase and traversal time in asymmetric graphene structures, revealing significant differences from semiconductor heterostructures due to graphene's unique Dirac-like charge carrier behavior and contact-induced symmetry breaking.

Contribution

It provides the first detailed analysis of how asymmetry and contacts affect Berry phase and traversal time in graphene, highlighting the role of Dirac physics.

Findings

Berry phase differs significantly in contacted vs. non-contacted graphene.

Traversal time shows notable variations due to asymmetry and contact effects.

Graphene's Dirac-like evolution law introduces unique asymmetry effects.

Abstract

The Berry phase and the group-velocity-based traversal time have been calculated for an asymmetric non-contacted or contacted graphene structure, and significant differences have been observed compared to semiconductor heterostructures. These differences are related to the specific, Dirac-like evolution law of charge carriers in graphene, which introduces a new type of asymmetry. When contacted with electrodes, the symmetry of the Dirac equation is broken by the Schrodinger-type electrons in contacts, so that the Berry phase and traversal time behavior in contacted and non-contacted graphene differ significantly.