Splitting of electronic spectrum in paramagnetic phase of itinerant ferromagnets and altermagnets
arXiv:2509.23396 · doi:10.1103/73r4-gxsl
Abstract
We study self-energy effects induced by strong magnetic fluctuations in the paramagnetic phase of strongly-correlated itinerant magnets within the density functional theory combined with the dynamical mean field theory (DFT+DMFT approach) and its non-local extension. We show that both local and non-local magnetic correlations yield a splitting of the electronic spectrum in the paramagnetic phase, such that it closely resembles the DFT band structure in the ordered phase. We demonstrate these effects on -iron, half-metal CrO, van der Waals material CrTe, and altermagnet CrSb. Although the obtained split bands do not possess a certain spin projection, their splitting suppresses spectral weight at the Fermi level. Even when originating from local magnetic correlations, the splitting is strongly momentum dependent as a consequence of the orbital selectivity of non-quasiparticle states. The relative importance of non-local vs. local correlations depends on the proximity to half filling of states: closer to half filling, the role of local correlations increases.
7+6 pages, 5+3 figures. Accepted as Phys. Rev. B Letter