Two-Dimensional Spectroscopy of Two-Dimensional Materials

TL;DR

This paper introduces an efficient numerical method to simulate two-dimensional spectra of doped 2D semiconductors, capturing key experimental phenomena and addressing model limitations for realistic spectral analysis.

Contribution

The work presents a novel, exact numerical approach for simulating multi-time correlation functions in a model relevant to doped 2D semiconductors, improving understanding of spectral features.

Findings

Reproduces experimentally observed peak asymmetry and oscillations

Identifies model artifacts due to infinite hole mass

Develops a filtering method for realistic spectral simulations

Abstract

In this work we provide an exact and efficient numerical approach to simulate multi-time correlation functions in the Mahan-Nozi\`{e}res-De Dominicis model, which crudely mimics the spectral properties of doped two-dimensional semiconductors such as monolayer transition metal dichalcogenides. We apply this approach to study the coherent two-dimensional electronic spectra of the model. We show that several experimentally observed phenomena, such as peak asymmetry and coherent oscillations in the waiting-time dependence of the trion-exciton cross peaks of the two-dimensional rephasing spectrum, emerge naturally in our approach. Additional features are also present which find no correspondence with experimentally expected behavior. We trace these features to the infinite hole mass property of the model. We use this understanding to construct an efficient approach which filters out configurations associated with the lack of exciton recoil, enabling the connection to previous work and providing a route to the construction of realistic two-dimensional spectra over a broad doping range in two-dimensional semiconductors.