Interactions and magnetotransport through spin-valley coupled Landau levels in monolayer MoS$_{2}$

TL;DR

This study investigates the magnetotransport properties of monolayer MoS$_{2}$, revealing complex Landau level interactions, larger effective mass, and higher spin-orbit splitting than predicted, highlighting strong interaction effects.

Contribution

It provides the first detailed magnetotransport measurements of conduction band Landau levels in monolayer MoS$_{2}$, uncovering interaction effects and deviations from theoretical predictions.

Findings

Effective mass of 0.7 m_e, twice the predicted value.

Occupation of second spin-orbit split band at 15 meV, larger than expected.

Complex Landau level spectrum influenced by Zeeman and spin-valley interactions.

Abstract

The strong spin-orbit coupling and the broken inversion symmetry in monolayer transition metal dichalcogenides (TMDs) results in spin-valley coupled band structures. Such a band structure leads to novel applications in the fields of electronics and optoelectronics. Density functional theory calculations as well as optical experiments have focused on spin-valley coupling in the valence band. Here we present magnetotransport experiments on high-quality n-type monolayer molybdenum disulphide (MoS$_{2}$) samples, displaying highly resolved Shubnikov-de Haas oscillations at magnetic fields as low as $2~T$. We find the effective mass $0.7~m_{e}$, about twice as large as theoretically predicted and almost independent of magnetic field and carrier density. We further detect the occupation of the second spin-orbit split band at an energy of about $15~meV$, i.e. about a factor $5$ larger than predicted. In addition, we demonstrate an intricate Landau level spectrum arising from a complex interplay between a density-dependent Zeeman splitting and spin and valley-split Landau levels. These observations, enabled by the high electronic quality of our samples, testify to the importance of interaction effects in the conduction band of monolayer MoS$_{2}$.