Spin-Orbit Electrical Readout of Magnetic State in Ferromagnet/Topological Insulator Devices

Topological materials have recently garnered attention for their potential to enable control of electron spin in spintronic devices. In particular, topological insulator (TI) layers have been proposed as components in beyond-CMOS magnetoelectric spin-orbit (MESO) logic architectures [1]. Spin-to-charge conversion (SCC) arising from topologically protected spin-momentum locking in TI layers is predicted to generate an electromotive force capable of powering downstream computing circuits with favorable device-scaling characteristics. In this work, the canonical TI Bi₂Te₃ is used to detect and electrically read out the magnetization of a ferromagnetic (FM) layer. Micron-scale devices were fabricated using a three-step optical lithography process on Bi₂Te₃ thin films grown using molecular beam epitaxy. A large transverse SCC voltage was generated upon injection of a spin-polarized current from a FM Fe layer into the TI layer. Switching behavior in the transverse SCC voltage was observed when the in-plane magnetization of the FM layer was reversed by an external magnetic field. Our results highlight the potential of topological insulators for efficient spin-to-charge conversion, providing a pathway toward realizing energy-efficient beyond-CMOS computing technologies.

[1] S. Manipatruni et al., Nature 565, 35–42 (2019).