Two-dimensional bound excitons in the real space and Landau quantization space: a comparative study

TL;DR

This study compares the properties of two-dimensional excitons in monolayer WSe2 in real space and Landau quantization space, revealing how magnetic fields and Coulomb interactions influence exciton behavior and dominant electron-hole pair components.

Contribution

It provides a detailed comparison of exciton energy spectra in real space and Landau quantization space, highlighting the effects of magnetic fields and Coulomb interactions on exciton states.

Findings

Energy spectra in both spaces agree well.

Diamagnetic coefficients and RMS radius match experimental data.

Magnetic field and Coulomb interactions influence dominant electron-hole pair components.

Abstract

The Landau quantization space is based on the respective motion of the electron and hole in a magnetic field and can provide a new route to understand the bound exciton behaviors observed in the experiments. In this paper, we study the two-dimensional exciton properties of monolayer WSe$_2$ in both the real space and Landau quantization space. Focusing on the excitons of zero center-of-mass momentum, we calculate its energy spectrum in both spaces, with the results agreeing well with each other. We then obtain the diamagnetic coefficients and root-mean-square radius, which are consistent with the available $s$ state data in the experiment. More importantly, in the exciton state $nl$, we find that the dominant electron-hole pair component may shift with the magnetic field and the Coulomb interactions, and reveal that the magnetic field will drive the dominant component to be the free electron-hole pair $\{n_e=n+l-1,n_h=n-1\}$, whereas the Coulomb interactions drives it to be the pair of the lower index.