Spintorque resonance due to diffusive dynamics at the surface of a topological insulator
Abstract
We investigate spinorbit torques on magnetization in an insulating ferromagnetic layer that is brought into close proximity to a topological insulator (TI). In addition to the wellknown fieldlike spinorbit torque, we identify an anisotropic antidampinglike spinorbit torque that originates in a diffusive motion of conduction electrons. This diffusive torque is vanishing in the limit of zero momentum (i.e., for a spatially homogeneous electric field or current), but it may, nevertheless, have a strong impact on spintorque resonance at finite frequency provided the external field is neither parallel nor perpendicular to the TI surface. The required electricfield configuration can be created by a grated top gate.
 Publication:

Physical Review B
 Pub Date:
 June 2019
 DOI:
 10.1103/PhysRevB.99.214444
 arXiv:
 arXiv:1810.05828
 Bibcode:
 2019PhRvB..99u4444S
 Keywords:

 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Disordered Systems and Neural Networks;
 Condensed Matter  Materials Science
 EPrint:
 10 page main text, 3 figures