Sep 25. 2024, 15:00 — 15:20
Spin-current density functional theory (SCDFT) is a formally exact framework designed to handle the treatment of interacting many-electron systems in magnetic fields including spin-orbit coupling (SOC) at the level of the Scrödinger-Pauli equation. [1] Robust and accurate calculations of the electronic structure of these systems call for functional approximations that depend not only on the particle- and spin-densities and the particle- and spin-currents but explicitly also on the two-component Kohn-Sham spinors. [2] Focusing on time-reversal symmetric spin-orbit coupled states, we demonstrate that spin-currents can be added non-empirically to meta-GGA forms by invoking the SU(2) gauge principle, as for the SCAN form. [3] We also show by working within the Generalized Kohn-Sham approach, that the regular second-variational treatment of spin-orbit coupling is unable to match the self-consistent SCDFT results for the Rashba splittings. [4,5] The extension of the electron localization function -- a popular descriptor of molecular bonds and atomic shells -- to general non-collinearly magnetized states, open-shell solutions of the Pauli-Schrödinger equation, will also be presented. [6] All the extended forms and procedure discussed in this talk are implemented in the CRYSTAL program.
[1] "
Current- and spin-density-functional theory for inhomogeneous electronic systems in strong magnetic fields”, G. Vignale and Mark Rasolt, Phys.
Rev. B 37, 10685 (1988); "
Spin–orbit coupling in the spin-current-density-functional theory", K Bencheikh,
J. Phys. A: Math. Gen. 36 11929 (2003)
[2] "
U(1)×SU(2) gauge invariance made simple for density functional approximations”, S. Pittalis, G. Vignale, and F. G. Eich,
Phys. Rev. B 96, 035141 (2017)
[3] “
Spin-currents via the gauge-principle for meta-generalized-gradient exchange-correlation functionals”, J.K. Desmarais, J. Maul, B. Civalleri, A. Erba, G. Vignale, and S. Pittalis,
Phys. Rev. Lett. 132, 256401 (2024)[4] "
Generalized Kohn-Sham Approach for the Electronic Band Structure of Spin-Orbit Coupled Materials”, J.K. Desmarais, G. Ambrogio, G. Vignale, A. Erba, and S. Pittalis,
Phys. Rev. Mater. 8, 013802 (2024)
[5] "
Unveiling the Role of Spin Currents on the Giant Rashba Splitting in Single Layer WSe2”, A. Boccuni, B. Peluzo, F. Bodo, G. Ambrogio, M. Jefferson, D. Mitoli, G. Vignale, S. Pittalis, E. Kraka, J. Desmarais, A. Erba,
J. Phys. Chem. Lett. 15, 7442 (2024) (2024)
[6] "
Electron localization function for non-collinear spins”, J.K. Desmarais, G. Vignale, K. Bencheikh, A. Erba, S. Pittalis,
arXiv:2405.15530 (2024)
[Accepted in Phys. Rev. Lett.]