Electronic structure of ferromagnetic semiconductor CrGeTe3 by angle-resolved photoemission spectroscopy

As one of the rare ferromagnetic semiconductors, ${\mathrm{CrGeTe}}_{3}$ has recently attracted a great deal of attention as a potential candidate for next-generation high-performance nano-spintronic devices. In this study, by combining density functional theory calculations and angle-resolved photoemission spectroscopy measurements, we explore the electronic structure of ${\mathrm{CrGeTe}}_{3}$ directly. The low-lying valence bands are centered around the $\mathrm{\ensuremath{\Gamma}}$ point and mainly consist of Te $5p$ orbitals. The majority of the bands show almost no ${k}_{z}$ dispersion, consistent with its layered crystalline structure. Due to the higher hopping integral along the out-of-plane direction, however, bands comprised of ${p}_{z}$ orbitals exhibit significant ${k}_{z}$ dispersion. Furthermore, an indirect band gap of 0.38 eV is directly measured by surface electron doping with potassium deposition.