Giant and Anisotropic Spin Relaxation Time in van der Waals GeSe With Gate-Tunability.

The 2D materials are promising channel materials for spin transistors due to their natural spatial-confined carrier transport character. Nonetheless, electrical spin injection and detection in 2D semiconductors used to be challenging. This study reports high-efficient spin injection and transport in 2D GeSe, which exhibits moderate spin-orbit coupling (SOC) and extended spin diffusion lengths due to the van der Waals structure. The non-local magnetoresistance (MR) measurements show a maximum spin polarization of 18.31%, a long spin diffusion length of 255.98 nm, and a giant spin relaxation time of 17.6 ns at room-temperature. After cooling to 4.3 K, the elevated spin diffusion length further increases to 397.04 nm, with an elevated spin polarization of 25.38%, leading to the successful observation of local MR in a two-terminal lateral spin valve. Additionally, the spin transport characteristics are also tunable by gate voltages due to the field-dependent SOC and Rashba spin relaxation. This study highlights GeSe as an air-stable 2D semiconductor with anisotropic and gate-tunable spin transport capability. The results will remove the barriers to developing novel spintronic devices based on emerging 2D semiconductors.