Magnon Dispersions via Noncollinear Time-Dependent Density-Functional Perturbation Theory with Hubbard-Corrected Functionals

by Ermanno Botti (PSI)

Wednesday 14 Oct 2026, 15:00 → 16:00 Europe/Zurich

OVGA/200

Magnon dispersions are usually obtained indirectly, by mapping total energies onto a Heisenberg model. A more direct route is to compute the dynamical spin susceptibility, whose poles give the magnons without assuming any model Hamiltonian. TDDFPT gives access to this quantity efficiently through the Liouville–Lanczos approach, implemented in the TURBOMAGNON code of QUANTUM ESPRESSO. Combined with Hubbard functionals with U computed from first principles, this framework already reproduces the measured magnon dispersions of NiO and MnO. In this talk, I will present the current status of the implementation, the challenges encountered, and how we are addressing them. So far, the noncollinear resonant and antiresonant Sternheimer equations have been derived and implemented, including the Hartree and exchange-correlation kernel. The implementation of the Hubbard kernel is currently in progress. The final goal is an efficient, parameter-free computational tool for predicting spin dynamics in complex magnetic materials.