科研之友
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摘要
Magnetization dynamics of a nanomagnet, when strongly coupled with a topological insulator (TI) via the proximity interaction, is examined theoretically in the presence of electrical current on the TI surface under realistic transport conditions. Due to the spin-momentum interlock, the magnetic state and TI electron transport depend significantly on each other. Such an interdependence leads to a variety of nonlinear dynamical responses in all transport regimes including the scattering dominant diffusive cases. Generation of the anomalous Hall current, in particular, is found to be a key to the unique features that have not been observed previously. For instance, the anomalous Hall current can result in antiparallel alignment of the final magnetization state in reference to the effective driving magnetic field by inducing an extra term that counters the damping effect. Similarly the calculation also reveals steady oscillation of the magnetization under a broad range of conditions, offering a robust mechanism for highly efficient magnetization reversal and/or spin wave excitation under a dc bias.
- 出版日期2015-9-18
