Charge-transfer-induced depth redistribution of surface spin states in the topological insulator
Phys. Rev. B 113, 075412 – Published 9 February, 2026
DOI: https://doi.org/10.1103/jf8w-95k3
Abstract
The spatial distribution of interfacial spin states is a critical factor governing the efficiency of spin-injection and spin-detection in spintronic devices. In this study, we use angle-resolved photoemission spectroscopy (ARPES) to investigate the evolution of the two types of spin-polarized surface states of the topological insulator —the topological surface states and the Rashba-type surface states (RSS)—upon electron doping. Our detailed analysis reveals that the electronic structure undergoes a modification that goes beyond a simple rigid band shift. Specifically, we observe that the electron doping reduces the ARPES intensity of one of the spin-split RSS branches. Calculations based on the density functional theory reveal that the decrease in intensity results from a change in the depth distribution of the probability densities. These results demonstrate that charge transfer can redistribute the near-surface weight of spin-polarized states along the surface normal, providing a depth degree of freedom for interfacial spins.
