Van der Waals contact between 2D magnetic VSe 2 and transition metals and demonstration of high-performance spin-field-effect transistors

This study used density functional theory and the quantum transport method to investigate the interfacial coupling and spin transport of transition metals (TMs) with a Fe, Co, and Ni/2H-VSe2 hybrid nanostructure. Because the indirect coupling of TM-Se-V led to an obvious reduction of the magnetic moment and the disappearance of the half-metal characteristics of 2H-VSe2, the expected spin-filtering effect of individual TMs and 2H-VSe2 deteriorated at the contact region. Nevertheless, all the TM/2H-VSe2-based dual-probe devices exhibited an interesting bias-dependent spin-injection efficiency with a maximum output spin-polarized current of 666 mA mm−1 in Co/2H-VSe2. The proposed TM/2H-VSe2-based spin-field-effect transistor demonstrated outstanding performance. The Ni/2H-VSe2-based transistor achieved a maximum output spin-polarized current of 3117 mA mm−1 and demonstrated a good switching characteristic of 106 mV dec−1. Importantly, all transistors achieved a widely tunable scale of spin extraction efficiency ranging consistently between 96% and −92% with gate bias. These results indicate a promising candidate for use in high-performance spintronic devices.