Mobility anisotropy in monolayer black phosphorus due to charged impurities

TL;DR

This paper investigates how charged impurities affect the anisotropic electrical mobility in monolayer black phosphorus, revealing a higher anisotropy ratio than in multilayer samples and analyzing its dependence on carrier density and impurity distribution.

Contribution

The study provides a detailed theoretical analysis of charged impurity effects on mobility anisotropy in monolayer black phosphorus using Boltzmann transport calculations.

Findings

Anisotropy ratio of 3-4 at zero temperature

Higher than experimental values in multilayer samples

Dependence of anisotropy on carrier density and impurity distribution

Abstract

We study the charged impurity limited mobility in black phosphorus, a highly anisotropic layered material. We compute the mobility within the Boltzmann transport equation under detailed balance condition, and taking into account the anisotropy in transport and electronic structure. For carrier densities accessible in experiments, we obtained an anisotropy ratio of 3 ~ 4 at zero temperature, two-folds larger than that observed in experiments on multilayers samples. We discuss also how the anisotropy depends on carrier density and impurity distribution.