Abstract
Using response theory, we calculate the charge current vortex generated by spin pumping at a point-like contact in a system with Rashba spin–orbit coupling (SOC). We discuss the spatial profile of the current density for finite temperature and for the zero-temperature limit. The main observation is that the Rashba spin precession leads to a charge current that oscillates as a function of distance from the spin pumping source, which is confirmed by numerical simulations. In our calculations, we consider a Rashba model on a square lattice, for which we first review the basic properties related to charge and spin transport. In particular, we define the charge current and spin current operators for the tight-binding Hamiltonian as the currents coupled linearly with the U(1) and SU(2) gauge potentials, respectively. By analogy to the continuum model, the SOC Hamiltonian on the lattice is then introduced as the generator of the spin current.
Highlights
Generation and detection of non-equilibrium spin angular momentum are of crucial importance in spintronics
For the two-dimensional (2D) Rashba model, which is an important example for the (I)spin Hall effect (SHE), we show that the charge current in such a configuration forms a vortex whose spatial profile indicates the strength of the SOC9
Spin–orbit coupling phenomena, such as the spin Hall effect, are of central importance in spintronics, as they facilitate the conversion between spin and charge degrees of freedom
Summary
Generation and detection of non-equilibrium spin angular momentum are of crucial importance in spintronics. We consider a Rashba system on a square lattice with one site coupled to a classical spin (Fig. 2). We introduce the charge current and spin current operators for the lattice model and show explicitly that in the long-wavelength limit, they become equivalent to their counterparts for the free-electron model. Considering the model on a square lattice, we define the charge and spin currents in Secs. III and IV, respectively, by using the local U(1) and SU(2) gauge transformations These definitions are consistent with the ordinary ones, in which the currents are introduced through the corresponding polarizations and their time derivatives. The Appendix discusses the lattice versions of the continuity equations for charge and spin
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
