Tailoring spin and electronic structure of MoS2 monolayer via interaction with substrate

MoS2 monolayer is a prominent direct band semiconductor. The band gap is 1.8eV and

located at K and K' points in the Brillouin zone. Using circularly polarized light, one can

separately excite electrons in K‐ and K+ valleys (the regions of K and K' points). Electrons in Kand

K+ valleys feature opposite out‐of‐plane spin and cannot easily change the valley. This

property is called spin‐valley locking. One can excite electrons with a particular spin using

circularly polarized light.

In the presented work, we manipulate the electronic and spin structure of MoS2 via

interaction with a substrate, to potentially gain control over MoS2 optical properties. We

demonstrate the Rashba effect in the MoS2 in‐plane spin structure in the MoS2/Au(111)

system. At the same time, due to symmetry reasons, the Rashba effect does not influence the

regions of K and K' points, which are interesting from the point of view of optical

implementation.

In order to manipulate the MoS2 spin structure in the K and K' points regions, we use the

magnetic proximity effect between the MoS2 monolayer and the cobalt thin film in the

MoS2/graphene/Co(0001) system. We place graphene between MoS2 and Co(0001) to prevent

possible excitons, potentially able to mediate spin flipping effects in the MoS2 monolayer,

from dissipating to the metallic substrate. We demonstrate that the magnetic proximity effect

causes the Zeeman splitting in MoS2 valence band states in the region of Г point and a spin tilt

toward in‐plane direction of the conduction band states in the regions of K and K' valleys.