Si-Joon Song

Investigation of electronic structure of amorphous, metastable, and stable phases of Ge1Sb2Te4 film by high-resolution x-ray photoemission spectroscopy

The electronic structures of amorphous, metastable, and stable phases of Ge1Sb2Te4 film were investigated by high-resolution x-ray photoelectron spectroscopy. The Te 4d core level showed a negligible change in binding energy (BE). In the stable phase, the Ge 3d and Sb 4d core levels were, respectively, dominated by a spin-orbit-split feature at 0.1eV-lower BE and a well-defined component at 0.4eV-higher BE than those in the amorphous phase. The analysis suggests that the amorphous phase and the stable phase is respectively represented by a broad and a well-defined electronic structure and that the metastable phase is represented by two different kinds of local electronic structures. The valence-band structures showed a trend similar to that reported by Klein et al. [Phys. Rev. Lett. 100, 016402 (2008)] between the amorphous and metastable phases.