Spin Dynamics Modulated by Rashba States in Ferroelectric α-GeTe

Abstract Ferroelectric Rashba semiconductor α-GeTe provides a promising arena in spintronics due to its large bulk and surface Rashba. Since most surface Rashba bands are located above Fermi level, the spin dynamics are mainly dominated by bulk states. Whether the surface states of α-GeTe can modulate the spin dynamics or not is an open question. Here, we report the manipulation of magnetic damping by the surface states of α-GeTe via ferromagnetic resonance (FMR) and theory calculation. The surface states located near the Fermi level of α-GeTe is realized by doping Bi atoms and revealed by angle-resolved photoemission spectroscopy (ARPES). Moreover, the magnitude of magnetic damping is related to the density of states near Fermi surfaces of Ge1 − xBixTe. Our work improves the understanding of the magnetic damping influenced by different part of Rashba bands and gives a platform for the research of α-GeTe in Rashba effect and the spintronics.