Tunable effective masses of magneto-excitons in two-dimensional materials

TL;DR

This paper investigates how applying a magnetic field can tune the effective mass of magneto-excitons in two-dimensional materials like Xanes, revealing a quadratic relationship between the field and exciton mass.

Contribution

It introduces a model demonstrating how magnetic fields can effectively control exciton masses in 2D semiconductors, a novel approach for excitonic property manipulation.

Findings

Magnetic field induces a quadratic negative shift in exciton energy.

Effective mass of magneto-excitons can be widely tuned by magnetic field strength.

Results applicable to low effective mass 2D semiconductors like Xanes.

Abstract

Excitonic properties of Ge$_2$H$_2$ and Sn$_2$H$_2$, also known as Xanes, are investigated within the effective mass model. A perpendicularly applied magnetic field induces a negative shift on the exciton center-of-mass kinetic energy that is approximately quadratic with its momentum, thus pushing down the exciton dispersion curve and flattening it. This can be interpreted as an increase in the effective mass of the magneto-exciton, tunable by the field intensity. Our results show that in low effective mass two-dimensional semiconductors, such as Xanes, the applied magnetic field allows one to tune the magneto-exciton effective mass over a wide range of values.