Carrier Plasmon Induced Nonlinear Band Gap Renormalization in Two-Dimensional Semiconductors

TL;DR

This paper introduces a new plasmon-pole theory to accurately model how doping-induced carrier plasmons cause significant, nonlinear band gap renormalization in 2D semiconductors like MoS2, enabling advanced band gap engineering.

Contribution

A novel plasmon-pole approach that captures nonlinear band gap changes due to carrier plasmons in doped 2D semiconductors, improving understanding of many-body effects.

Findings

Band gap renormalization of ~400 meV in MoS2

Nonlinear evolution of band gap with doping

Significant difference from 1D structures' behavior

Abstract

In reduced-dimensional semiconductors, doping-induced carrier plasmons can strongly couple with quasiparticle excitations, leading to a significant band gap renormalization. We develop a new plasmon-pole theory that efficiently and accurately capture this coupling. Using monolayer molybdenum disulfide (MoS2) as a prototype two-dimensional (2D) semiconductor, we reveal an enhanced band gap renormalization around 400 meV and an unusual nonlinear evolution of its band gap with doping. This 2D prediction significantly differs from the linear behaviors that are common to one-dimensional structures. Our developed approach allows for a quantitative understanding of many-body interactions in general doped 2D semiconductors and paves the way for novel band gap engineering techniques.