Strain engineering the charged-impurity-limited carrier mobility in phosphorene

TL;DR

This study models how uniaxial strain affects the electronic band structure and charged-impurity-limited carrier mobility in phosphorene, revealing strain-direction-dependent modifications to mobility anisotropy.

Contribution

It introduces a strain-dependent decoupled electron-hole Hamiltonian to analyze the effects of uniaxial strain on phosphorene's electronic properties and carrier mobility.

Findings

Normal direction tensile strain increases mobility anisotropy.

Zigzag direction strain decreases mobility anisotropy.

Armchair direction strain has negligible effect on anisotropy.

Abstract

We investigate, based on the tight-binding model and in the linear deformation regime, the strain dependence of the electronic band structure of phosphorene, exposed to a uniaxial strain in one of its principle directions, the normal, the armchair and the zigzag directions. We show that the electronic band structure of strained phosphorene, for experimentally accessible carrier densities and uniaxial strains, is well described by a strain-dependent decoupled electron-hole Hamiltonian. Then, employing the decoupled Hamiltonian, we consider the strain dependence of the charged-impurity-limited carrier mobility in phosphorene, for both types of carrier, arbitrary carrier density and in both armchair and zigzag directions. We show that a uniaxial tensile (compressive) strain in the normal direction enhances (weakens) the anisotropy of the carrier mobility, while a uniaxial strain in the zigzag direction acts inversely. Moreover applying a uniaxial strain in the armchair direction is shown to be ineffective on the anisotropy of the carrier mobility. These will be explained based on the effect of the strain on the carrier effective mass.