Electrons and holes in phosphorene

TL;DR

This paper provides a symmetry-based analysis of the electronic bandstructure in monolayer black phosphorus, revealing anisotropic optical and transport properties, and explaining valence band distortion and potential indirect gap nature.

Contribution

It introduces a symmetry analysis framework for electrons and holes in phosphorene, elucidating anisotropic behaviors and mechanisms behind valence band features.

Findings

Identifies symmetry origins of anisotropic optical absorption.

Explains charge and spin transport anisotropy.

Reveals mechanisms for valence band distortion and indirect gap possibility.

Abstract

We present a symmetry analysis of electronic bandstructure including spin-orbit interaction close to the insulating gap edge in monolayer black phosphorus ('phosphorene'). Expressions for energy dispersion relation and spin-dependent eigenstates for electrons and holes are found via simplification of a perturbative expansion in wavevector $k$ away from the zone center using elementary group theory. Importantly, we expose the underlying symmetries giving rise to substantial anisotropy in optical absorption, charge and spin transport properties, and reveal the mechanism responsible for valence band distortion and possible lack of a true direct gap.