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MM: Fachverband Metall- und Materialphysik

MM 6: Transport in Materials: Ion, Charge and Heat Transport

MM 6.8: Vortrag

Montag, 27. März 2023, 12:15–12:30, SCH A 118

Spin Hall effect in tungsten and tantalum via first-principles calculations — •Reena Gupta, Stefano Sanvito, and Andrea Droghetti — School of Physics and CRANN, Trinity College, 2, Dublin, Ireland

We study theoretically the spin Hall effect (SHE), a phenomenon where a longitudinal charge current in a material sample gets converted into a transverse spin current and leads to spin accumulation on the sample boundaries. The common theoretical methods to calculate the intrinsic SHE conversion efficiency (i.e., the "spin Hall angle") are semi-classical or rely on the relaxation time approximation. To go beyond these limitations, we combine the non-equilibrium Green's function approach with Density Functional Theory. We study the SHE in bulk as well as slab geometries for different phases of tungsten and tantalum. We find values for the spin Hall angles, which are comparable to the most recent experimental results. Furthermore, in the slab geometries, we find that the spin Hall effect is accompanied by current-induced spin polarization (CISP). We then discuss the relative magnitude of the SHE and of CISP suggesting how the two effects can be distinguished in experiments.