Band Renormalization in Monolayer MoS2 Induced by Multipole Screening

TL;DR

This study reveals that dielectric screening causes non-rigid, momentum-dependent band renormalization in monolayer MoS2, influenced by temperature and interlayer separation, challenging the traditional rigid band shift view.

Contribution

It provides experimental evidence of momentum-dependent band renormalization in 2D materials due to multipole screening effects, expanding understanding of dielectric influences.

Findings

Temperature affects dielectric screening and band structure in monolayer MoS2.

Screening transitions from monopole to multipole regime at low temperatures.

Band shifts are momentum-dependent at cryogenic temperatures.

Abstract

Dielectric screening plays a crucial role in shaping the electronic structure of two-dimensional (2D) materials. In 2D semiconductors, screened Coulomb interactions arising from the surrounding dielectric environment are known to induce band renormalization, which is typically understood as a rigid shift of the electronic bands. Here, we experimentally demonstrate that dielectric screening can also give rise to non-rigid, momentum-dependent band renormalization. Using temperature-dependent angle-resolved photoemission spectroscopy (ARPES), we observe pronounced changes in the electronic band structure of monolayer MoS2 on a highly oriented pyrolytic graphite (HOPG) substrate. The results indicate that temperature-driven variations in the effective interlayer separation modulate the dielectric screening experienced by monolayer MoS2. At room temperature, the screening behavior is well described by a momentum-independent monopole approximation, whereas at liquid-helium temperatures the screening evolves into a multipole-like regime, leading to momentum-dependent band shifts.