The impact of valley profile on the mobility and Kerr rotation of transition metal dichalcogenides

TL;DR

This paper presents a first-principle model linking valley positions in transition metal dichalcogenides to their mobility and Kerr rotation, offering insights and predictions for optimizing electronic and optical properties.

Contribution

The study introduces a novel first-principle model that predicts how valley positions affect mobility and Kerr rotation in transition metal dichalcogenides, enabling in situ characterization.

Findings

Mobility exhibits a doping-dependent peak influenced by valley positions.

Kerr rotation is enhanced with aligned same spin-valleys and quenched with opposite spin-valleys.

The model provides guidelines for experimental optimization of valley-related properties.

Abstract

The transport and optical properties of semiconducting transition metal dichalcogenides around room temperature are dictated by electron-phonon scattering mechanisms within a complex, spin-textured and multi-valley electronic landscape. The relative positions of the valleys are critical, yet they are sensitive to external parameters and very difficult to determine directly. We propose a first-principle model as a function valley positions to calculate carrier mobility and Kerr rotation angles. The model brings valuable insights, as well as quantitative predictions of macroscopic properties for a wide range of carrier density. The doping-dependant mobility displays a characteristic peak, the height depending on the position of the valleys. The Kerr rotation signal is enhanced when same spin-valleys are aligned, and quenched when opposite spin-valleys are populated. We provide guidelines to optimize these quantities with respect to experimental parameters, as well as the theoretical support for \emph{in situ} characterization of the valley positions.