Spin-orbit effects in a graphene bipolar pn junction

TL;DR

This paper theoretically investigates how spin-orbit interactions affect electron transmission in graphene pn junctions, revealing tunable reflection-transmission crossover and modifications to conductance and noise characteristics.

Contribution

It introduces a detailed analysis of spin-orbit effects in graphene pn junctions, highlighting the tunability of electron transmission via electric fields and distinguishing effects from trivial band gaps.

Findings

Crossover from perfect reflection to perfect transmission at normal incidence.

Spin-orbit effects modify conductance and Fano factor.

Angular dependence helps distinguish spin-orbit effects from trivial gaps.

Abstract

A graphene $pn$ junction is studied theoretically in the presence of both intrinsic and Rashba spin-orbit couplings. We show that a crossover from perfect reflection to perfect transmission is achieved at normal incidence by tuning the perpendicular electric field. By further studying angular dependent transmission, we demonstrate that perfect reflection at normal incidence can be clearly distinguished from trivial band gap effects. We also investigate how spin-orbit effects modify the conductance and the Fano factor associated with a potential step in both $nn$ and $np$ cases.