Unconventional Quantum Hall Effect and Tunable Spin Hall Effect in MoS2 Trilayers

TL;DR

This paper investigates the unique Landau level structure and spin Hall effects in MoS2 trilayers, revealing unconventional quantum Hall plateaus, spin-resolved conductance, and tunable spin Hall conductivity due to orbital and spin-orbit interactions.

Contribution

It introduces the analysis of Landau levels and spin Hall effects in MoS2 trilayers, highlighting the impact of orbital asymmetry and spin-orbit coupling on quantum Hall phenomena.

Findings

Unconventional Hall plateau sequence due to orbital asymmetry.

Field-dependent Landau level energies grow linearly with magnetic field.

Controllable spin-polarized current in p-n junctions.

Abstract

We analyze the Landau level (LL) structure and spin Hall effect in a MoS2 trilayer. Due to orbital asymmetry, the low-energy Dirac fermions become heavily massive and the LL energies grow linearly with $B$, rather than with $\sqrt{B}$. Spin-orbital couplings break spin and valley degenerate LL's into two time reversal invariant groups, with LL crossing effects present in the valence bands. We find a field-dependent unconventional Hall plateau sequence $\nu=...$ $-2M-6$, $-2M-4$, $-2M-2$, $-2M-1$, ..., -5, -3, -1, 0, 2, 4 .... In a p-n junction, spin-resolved fractionally quantized conductance appears in two-terminal measurements with a controllable spin-polarized current that can be probed at the interface. We also show the tunability of zero-field spin Hall conductivity.