QMC Colloquium: Kirill Belashchenko, University of Nebraska-Lincoln

Spin transport and spin-orbit torque in metallic heterostructures

 Current-induced spin-orbit torque enables electric control of magnetization in spintronic devices. I will start by discussing the basic phenomenology and mechanisms of spin-orbit torque. I will then discuss first-principles calculations of spin transport and spin-orbit torques in disordered films and multilayers using the nonequilibrium Green's function technique [1]. Of particular interest is the generation of spin-orbit torque with unconventional spin polarization that can enable the switching of magnetization perpendicular to the film plane; this requires certain symmetries to be broken. I will discuss unconventional torques in ferromagnet/nonmagnet/ferromagnet trilayers [2], as well as spin currents generated by the so-called spin-splitting effect in alter magnets [3] and anisotropic ferromagnets [4], which could be harnessed for this purpose.

 [1] K. D.Belashchenko, A. A. Kovalev, and M. van Schilfgaarde, Phys. Rev.Materials 3, 011401(R) (2019); Phys. Rev. B 101,020407(R) (2020).

[2] V. P. Amin,G. G. Baez Flores, A. A. Kovalev, and K. D. Belashchenko, Phys. Rev. B 110,214427 (2024).

[3] K. D.Belashchenko, Phys. Rev. Lett. 134, 086701 (2025).

[4] K. D.Belashchenko, Phys. Rev. B 109, 054409 (2024).