Fermi surface expansion above critical temperature in a Hund ferromagnet

Abstract

Using a cluster extension of the dynamical mean-field theory, we show that strongly correlated metals subject to Hund's physics exhibit significant electronic structure modulations above magnetic transition temperatures. In particular, in a ferromagnet having a large local moment due to Hund's coupling (Hund's ferromagnet), the Fermi surface expands even above the Curie temperature ($T_{\mathrm{C}}$) as if a spin polarization occurred. Behind this phenomenon, effective ``Hund's physics'' works in momentum space, originating from ferromagnetic fluctuations in the strong coupling regime. The resulting significantly momentum-dependent (spatially nonlocal) electron correlations induce an electronic structure reconstruction involving a Fermi-surface volume change and a redistribution of the momentum-space occupation. Our finding will give a deeper insight into the physics of Hund's ferromagnets above $T_{\mathrm{C}}$.

Main text: 6 pages, 4 figures. Supplemental Materials: 3 pages, 8 figures

References in corpus (9)

• Strong electronic correlations from Hund's coupling
• Coherence-incoherence crossover in the normal state of iron-oxypnictides and importance of the Hund's rule coupling
• Spin freezing transition and non-Fermi-liquid self-energy in a 3-orbital model
• Fluctuation diagnostics of the electron self-energy: Origin of the pseudogap physics
• Sub-matrix updates for the Continuous-Time Auxiliary Field algorithm
• Composite-Fermion Theory for Pseudogap, Fermi Arc, Hole Pocket, and Non-Fermi-Liquid of Underdoped Cuprate Superconductors
• Nonlocal correlations induced by Hund's coupling: a cluster DMFT study
• Itinerant ferromagnetism in the multiorbital Hubbard model: a dynamical mean-field study
• Spectral functions of 2D systems with coupling of electrons to collective or localized spin degrees of freedom

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• Experimental determination of the spin Hamiltonian of the cubic chiral magnet MnSi
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