Figure 3: Spin-orbit-induced splitting of the valence band in monolayer MoS₂.

(a) ARPES electronic structure measurements of monolayer MoS₂ on highly ordered pyrolytic graphite (HOPG) substrate along the high symmetry direction , showing the observation of MoS₂ monolayer electronic bands as well as the π bands of graphite at the point of the BZ. (b) First-principles calculated electronic structure measurements of monolayer MoS₂ accompanied by graphite along the high symmetry direction . (c) Zoomed-in version of the ARPES electronic structure spectra along the direction. (d) 2D curvature plot of the bands near the valence band top, showing the experimental observation of the predicted spin-orbit split valence band along . The green dotted lines are guides to the eyes for these two spin-orbit split branches of the valence band. Here the ARPES measurements were performed at photon energy of hν=110 eV and temperature of T=200 K. (e) First-principles calculated bands near the valence band top, confirming the experimental observation of the predicted spin-orbit split valence band. (f) Charge densities of conduction and valence states at . (g) Top view of monolayer MoS₂. The spin polarization of the V1 band is in the direction of a × b, provided that a is aligned along the direction.