Persistent current-carrying state of charge quasuparticles in $np$-ribbon featuring single Dirac cone

TL;DR

This paper investigates how persistent charge currents can spontaneously form in 2D electron-hole ribbons on topological insulators, driven by quantum interference effects at chiral junctions, revealing stable electron-hole quantum states with current flow.

Contribution

It demonstrates the formation of persistent currents in 2D Dirac fermion systems on topological insulators due to asymmetric scattering and quantum interference, a novel insight into charge transport.

Findings

Persistent currents arise without external bias.

Currents are due to interference at chiral junctions.

Electron-hole quantum states carry the currents.

Abstract

The formation of persistent charge currents in mesoscopic systems remains an interesting and actual topic of condensed matter research. Here, we analyze the formation of spontaneous arising persistent currents of charged fermions in 2-dimensional electron-hole ribbons on the top and bottom of a 3-dimensional topological insulator. In such a device the two-dimensional Dirac fermions with opposite chiralities are spatially separated that allows these currents to flow in the opposite directions without compensating each other. The nature of this phenomenon is based on the interference of the quasiparticle quantum waves which are scattered with asymmetric scattering phases at the lateral n-p chiral junction and then reflected back by the external boundaries of the ribbon. As a result quasiparticles in the ribbon are shown to be in unified electron-hole quantum states carrying the persistent current.