Controlled Growth of Semiconductor Alloy/Ferromagnetic Insulator (GeBi/Bi:Thulium Iron Garnet (TmIG)) Spin Heterojunction and Development of Quantum Logic Device

Abstract

Replacing heavy metal and heavy metal alloy films with a semiconductor thin film, to form a semiconductor/ferromagnetic insulator spin heterojunction has always been an international research hotspot. This article reports on a Ge1–xBix/Bi:thulium iron garnet (TmIG) spin heterojunction. It was found that Ge1–xBix (x = 0.06–0.22) semiconductor alloy films and Bi3+-doped control Tm3–yBiyFe4.3Ga0.7O12 (Bi:TmIG, y = 0.2–1.0) films can enhance the spin–orbit coupling (SOC) strength, improving the abnormal spin Hall effect (ASHE) and the spin Hall magnetoresistance (RH) switch characteristics. As x varies from 0.06 to 0.22, it is noticed that the spin mixing conductance considerably increases. Because Bi ions have the ability to control the SOC strength, the 5–10 nm GeBi semiconductor thin film with the Bi-ion-doped Bi:TmIG film can realize a spin magnetic moment reversal and then drive the heterojunction magnetic moment switching effect, and the spin currents injected across this interface lead to deterministic magnetization reversal at an ultralow current density of 1.82 × 106 mA/cm2. This has significant practical applications in the design and implementation of spin quantum logic devices based on semiconductor processes, laying a material foundation for the development of quantum logic devices.