Intrinsic spin Hall effect in monolayers of group-VIdichalcogenides: A first-principles study...

Usingfirst-principlescalculationswithindensityfunctionaltheory,weinvestigatetheintrinsicspinHalleffectinmonolayersofgroup-VItransition-metaldichalcogenidesMX2(M=Mo,WandX=S,Se).MX2monolayersaredirectband-gapsemiconductorswithtwodegeneratevalleyslocatedatthecornersofthehexagonalBrillouinzone.Becauseoftheinversionsymmetrybreakingandthestrongspin-orbitcoupling,chargecarriersinoppositevalleyscarryoppositeBerrycurvatureandspinmoment,givingrisetobothavalley-Hallandaspin-Halleffect.WealsoshowthattheintrinsicspinHallconductivityininversion-symmetricbulkdichalcogenidesisanorderofmagnitudesmallercomparedtomonolayers.Ourresultdemonstratesmonolayerdichalcogenidesasanidealplatformfortheintegrationofvalleytronicsandspintronics.