Speaker: Miguel A. Cazalilla, National Tsinghua University, Hsinchu, Taiwan
Abstract
We theoretically show that two dimensional metals like graphene, for which the effects of spin-orbit coupling in the band structure are essentially negligible, can still be used for spin current generation resulting from the extrinsic spin-Hall effect if they are “decorated” with various kinds of absorbates [1]. In addition, they can also magnetize in response to the application of an electric field [2]. We point out that a sizable contribution to this current-induced non equilibrium magnetization arises from a newly discovered direct magneto-electric coupling, which we termed anisotropic spin-precession scattering (ASP) [2,4]. Signatures of the ASP in nonlocal resistance measurements will be also discussed [3]. We will also argue that the new mechanism is a fairly universal phenomenon in disordered spin-orbit coupled systems lacking inversion symmetry [4]. Thus, it should be relevant for the understanding of spin-charge conversion mechanisms, which can have many potential applications. Time permitting, a brief discussion to the controversial experimental situation in graphene decorated with adatoms will be provided, as well as some alternative explanations to the observed phenomena [5].
[1] A. Ferreira, T. Rappoport, MAC, and A. H. Castro Neto, Phys. Rev. Lett 112, 066601 (2014);
H.-Y. Yang, C. Huang, H. Ochoa, and MAC, Phys. Rev. B 93 085418 (2014).
C. Huang, Y. Chong, G. Vignale, and MAC, Phys. Rev. B 93, 165429 (2016).
[2] C. Huang, Y. Chong, and MAC, Phys. Rev. B Phys. Rev. B 94, 085414 (2016).
[3] C. Huang, Y. Chong, and MAC, Phys. Rev. Lett. . 119, 136804 (2017).
[4] C. Huang, M. Milletari, MAC, Phys. Rev. B 96, 205305 (2017).
[5] X.-P. Zhang, C. Huang, and MAC,: 2D Materials, 4 024007 (2017); ibid to be published.
Time: 14:00 pm, Apr. 9 (Monday), 2018
Venue: Rm. N313, UCAS Teaching Building [View Map]
