First-Principles Transport Including Magnetic and Spin-Orbit Effects

Topology is the next frontier in materials science, opening possibilities for ultra low power devices, exquisite sensing capabilities, and synergies with quantum computing through the protection of state coherence.<br/><br/>We will showcase recent advances in the theory and applications of first-principles transport calculations, to include magnetism and spin-orbit interactions, and what will be needed to tackle the most complex topological materials, which contain both effects. Using spinor wave functions and SOI naturally incorporates spin-flip processes in electron-phonon scattering. Comparisons to experiments on "simple" 3d ferromagnetic metals require the inclusion of electron-magnon scattering, both in resistivity and in magnon drag.<br/><br/>As a next step into topology, we showcase the first-principles conductivity of Weyl semi-metals, in particular TaAs for which our calculations are in very good agreement with available experiments. Finally, magnetoelectrically-active 2D Nickel Iodide (NiI2) can host topological magnetic states, and we find that it shows strong sensitivity to pressure. Combining experimental characterization with first and second principles simulations, we determine the pressure dependency (up to 20 GPa) of the electronic band structure, magnetic phase transition, and spinwave dispersion.<br/><br/>- X Ma et al. New Journal of Physics 25, 043022<br/>- G Allemand and MJ Verstraete, unpublished (2023)<br/>- J Kapeghian et al. arxiv.org/abs/2306.04729