Effect of gadolinium doping on the electronic band structure of europium oxide

Abstract

High quality films of EuO and Eu${}_{0.96}$Gd${}_{0.04}$O were grown on $p$-type Si(100) via pulsed laser deposition. X-ray-diffraction results show that the addition of Gd changes the growth texture from [001] to [111]. Angular-resolved photoemission spectroscopy reveals electron pockets around the $X$ points in Gd-doped EuO, indicating that the band gap in EuO is indirect. Combined photoemission and inverse photoemission measurements show an apparent transition from $n$-type to $p$-type behavior, which is likely due to band bending near the polar (111) surface.