Mass Renormalization in Transition Metal Dichalcogenides

TL;DR

This paper demonstrates how Coulomb interactions, influenced by dielectric environment, cause mass renormalization of electrons and holes in transition metal dichalcogenides, affecting excitonic properties and aligning well with experimental data.

Contribution

It reveals the impact of Coulomb interactions on effective mass renormalization in transition metal dichalcogenides and its dependence on dielectric surroundings.

Findings

Mass renormalization varies with dielectric environment.

Effective exciton mass decreases with hBN encapsulation.

Theoretical results agree with high field experimental measurements.

Abstract

It is shown that the three-fold rotational symmetry in transition metal dichalcogenides leads to a Coulomb induced renormalization of the effective electron and hole masses near the $K$-points of the Brillouin zone. The magnitude of the renormalization depends on the dielectric configuration. The effective exciton mass $m=0.4 m_0$ of a freely suspended MoS$_2$ monolayer changes to $m= 0.35 m_0$ with hBN encapsulation. The mass renormalization increases the excitonic binding energy and reduces the exciton diamagnetic shift and cyclotron frequency. Detailed comparisons with high field measurements of the excitonic diamagnetic shift show excellent agreement.