Electronic structure of zinc-blende MnTe investigated by photoemission and inverse-photoemission spectroscopies

Abstract

Valence-band and conduction-band electronic structure of zinc-blende MnTe (111) epitaxial film has been investigated by ultraviolet photoemission and inverse-photoemission spectroscopies (UPS and IPES). The UPS and IPES spectra exhibit peak structures at $\ensuremath{-}1.5,$ $\ensuremath{-}3.4,$ and $\ensuremath{-}4.3$ eV, and at 3.5 and 6.7 eV relative to the valence-band maximum, respectively. Based on a one-electron band-structure calculation, peaks at $\ensuremath{-}3.4$ and 3.5 eV are assigned to emissions from the occupied Mn $3d\ensuremath{\uparrow}$ and unoccupied Mn $3d\ensuremath{\downarrow}$ states with nearly localized character. From their energy positions, a Mn $3d$ exchange splitting energy is estimated to be $6.9\ifmmode\pm\else\textpm\fi{}0.2$ eV, which is close to that of ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Te}$ $(7.0\ifmmode\pm\else\textpm\fi{}0.2$ eV) and is slightly larger than that of NiAs-type MnTe $(6.6\ifmmode\pm\else\textpm\fi{}0.2$ eV).