Giant Hall Switching by Surface-State-Mediated Spin-Orbit Torque in a Hard Ferromagnetic Topological Insulator

ORAL

Abstract

Topological insulators (TI) and magnetic topological insulators (MTI) can apply highly efficient spin-orbit torque (SOT) and manipulate the magnetization with their unique topological surface states with ultra-high efficiency. Here, we demonstrate efficient SOT switching of a hard MTI, V-doped (Bi,Sb)2Te3 (VBST) with a large coercive field that can prevent the influence of an external magnetic field. A giant switched anomalous Hall resistance of 9.2 kΩ is realized, among the largest of all SOT systems. The SOT switching current density can be reduced to 2.8×105 A/cm2. Moreover, as the Fermi level is moved away from the Dirac point by both gate and composition tuning, VBST exhibits a transition from edge-state-mediated to surface-state-mediated transport, thus enhancing the SOT effective field to 1.56±0.12 T/ (106 A/cm2) and the spin Hall angle to 23.2±1.8 at 5 K. The findings establish VBST as an extraordinary candidate for energy-efficient magnetic memory devices.

*The authors acknowledge the support from the National Science Foundation (NSF) (DMR-1411085 and DMR-1810163) and the Army Research Office Multidisciplinary University Research Initiative (MURI) under grant numbers W911NF16-1-0472 and W911NF-19-S-0008. In addition, H.Z. acknowledges support from the U.S. Department of Commerce, NIST under financial assistance award 70NANB19H138. A.V.D. acknowledges support from the Material Genome Initiative funding allocated to NIST.

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Publication: L. Tai, H. He, S. K. Chong, H. Zhang, G. Qiu, Y. Li, H.-Y. Yang, T.-H. Yang, X. Dong, Y. Ren, … K. L. Wang. "Giant Hall Switching by Surface-State-Mediated Spin-Orbit Torque in a Hard Ferromagnetic Topological Insulator." arXiv: 2306.05603 (2023).

Presenters

  • Lixuan Tai

    • University of California, Los Angeles
    • Department of Electrical and Computer Engineering, University of California, Los Angeles

Authors

  • Lixuan Tai

    • University of California, Los Angeles
    • Department of Electrical and Computer Engineering, University of California, Los Angeles