Electronic structure and metal-insulator transition in crystalline magnetic phase-change material Ge1−xFexTe

Abstract

X-ray photoemission spectroscopy (XPS) and carrier transport measurements were used to investigate the electronic structure of crystalline Ge1−xFexTe films across the metal-insulator transition. Both valence-band XPS analysis and transport properties indicate that the Fermi energy is shifted downward with increasing Fe concentration. This shift is ascribed to that the incorporated Fe atoms give rise to shallow states near the Fermi energy. Temperature-dependent resistivity measurements reveal that Ge1−xFexTe films undergo a transition from insulating to metallic state at Fe concentration x above 0.1. This metal-insulator transition is attributed to disorder-induced Anderson localization.