Unconventional Quantum Hall Effect and Tunable Spin Hall Effect in Dirac Materials: Application to an Isolated MoS2 Trilayer

We analyze the Landau level (LL) structure in a MoS2 trilayer and find a field-dependent unconventional Hall plateau sequence v = . . ., -2M -6, -2M -4, -2M -2, -2M -1, . . ., -5, -3, -1, 0, 2, 4, . . .. Because of orbital asymmetry, the low-energy Dirac fermions become heavily massive and the LL energies grow linearly with B, rather than with root B. Spin-orbital couplings break spin and valley degenerate LL's into two groups, with LL crossing effects present in the valence bands. 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. DOI: 10.1103/PhysRevLett.110.066803