Consequently, the VBM in Sc2Si2Te6 is located at Γ (rather than Z), is doubly (rather than singly) degenerate and exhibits reduced band dispersion. As expected due to the presence of heavy elements Te and (to a lesser extent) Sb, spin-orbit coupling (SOC) is found to significantly reduce the band gaps of these compounds, contributing VBM upshifts of 0.2-0.3 eV (Figure ). The VBM is set to zero. (c) Charge density isosurface of the Sc2Si2Te6 CBM state. The isosurface level is set to 0.02eV/Å 3 .