Emergence of giant orbital Hall and tunable spin Hall effects in centrosymmetric transition metal dichalcogenides

We demonstrate the formation of orbital and spin Hall effects (OHE/SHE) in the 1T phase of nonmagnetic transition metal dichalcogenides. With the aid of density functional theory calculations and model Hamiltonian studies on ${MX}_{2}$ ($M$ = Pt, Pd; and $X$ = S, Se, and Te), we show an intrinsic orbital Hall conductivity ($\ensuremath{\sim}{10}^{3}\ensuremath{\hbar}/e\phantom{\rule{4pt}{0ex}}{\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}1}{\text{cm}}^{\ensuremath{-}1}$), which primarily emerges due to the orbital texture around the valleys in the momentum space. The robust spin-orbit coupling in these systems induces a sizable SHE out of OHE. Furthermore, to resemble the typical experimental setups, where the magnetic overlayers produce a proximity magnetic field, we examine the effect of magnetic field on OHE and SHE and showed that the latter can be doubled in these class of compounds. With a giant OHE and tunable SHE, the 1T-TMDs are promising candidates for spin and orbital driven quantum devices such as SOT-MRAM, spin nano-oscillators, spin logic devices, etc., and to carry out spin-charge conversion experiments for fundamental research.