Room-temperature sign reversed spin accumulation signals in silicon-based devices using an atomically smooth Fe3Si/Si(111) contact

Abstract

We demonstrate a reliable sign-reversed spin signal detected by three-terminal Hanle effect measurements at room temperature in the Si-based lateral devices with one ${\text{Fe}}_3\text{Si}/\text{Si}(111)$ Schottky-tunnel contact. Theoretical calculations of the spin polarized density of states suggest the sign difference in the spin polarization (P) between the two types of ${\text{Fe}}_3\text{Si}/\text{Si}(111)$ interfaces. Actually, we directly observe the atomic steps at the ${\text{Fe}}_3\text{Si}/\text{Si}(111)$ interface, implying that there is a possible origin of the sign difference in the spin polarization (P) between spin-injection region and spin-detection one in one contact. The reliable sign-reversed spin signals support that the injected spins are transported laterally in the Si channel even for the three-terminal Hanle-effect measurements.