Effect of two-dimensional nonlocal screening on mobility of electrons in transition-metal dichalcogenide monolayers

TL;DR

This paper introduces a new model for electron scattering in transition-metal dichalcogenide monolayers that accounts for two-dimensional nonlocal screening, significantly enhancing the predicted electron mobility, especially at room temperature.

Contribution

It develops a theoretical framework incorporating nonlocal screening effects into electron mobility calculations in TMD monolayers, providing more accurate predictions.

Findings

Nonlocal screening increases electron mobility by several times.

Mobility decreases with temperature, but the relative enhancement grows at room temperature.

The model aligns with experimental observations of mobility in TMD monolayers.

Abstract

A new mechanism for charge carrier scattering in transition-metal dichalcogenide monolayers is proposed on the basis of the theory of two-dimensional nonlocal screening developed for the dielectric function of thin-layer insulating materials (P. Cudazzo et al. PRB 84, 085406 (2011)). The expressions for the transport relaxation time and for the electron mobility are obtained for electrons scattering on Coulomb impurity centers in monolayers of transition-metal dichalcogenide on various substrates. It is found that taking nonlocal screening into account increases the mobility of electrons by several times. Although the value of the mobility decreases with increasing temperature, the relative enhancement due to nonlocal screening grows 6-9 times at room temperature, in the case of SiO$_2$ substrate.