First-principles Study of Carrier Mobility in MX (M=Sn, Pb; X=P, As) Monolayers

TL;DR

This study uses first-principles calculations to analyze carrier mobility in MX monolayers, revealing key electronic properties and the potential of SnP for future 2D semiconductor applications.

Contribution

It provides new insights into the electronic properties and mobility of MX monolayers, especially highlighting the effects of strain on SnP's mobility.

Findings

SnP has the highest electron mobility among studied monolayers.

PbP exhibits a direct band gap, unlike others with indirect gaps.

Strain significantly enhances SnP's electron mobility to 2,511.9 cm^2/Vs.

Abstract

Compounds from groups IV and V have been the focus of recent research due to their impressive physical characteristics and structural stability. In this study, the MX monolayers (M=Sn, Pb; N=P, As) are investigated with first-principles calculations based on Boltzmann transport theory. The results show that SnP, SnAs, and PbAs all exhibit indirect band gaps, whereas PbP is the only semiconductor with a direct band gap. One important finding is that intravalley scattering has a significant impact on electron-phonon coupling. Interestingly, changes in carrier concentration do not affect the electron mobility within these MX monolayers, with SnP exhibiting the highest electron mobility among them. Subsequently, the SnP under a 6% biaxial strain is further explored and the results demonstrated a considerable increase in electron mobility to 2,511.9 cm^2/Vs, which is attributable to decreased scattering. This suggests that MX monolayers, especially SnP, are promising options for 2D semiconductor materials in the future.