2020/04/01 by Changming Yue, Philipp Werner · 5 citations
Materials Science · Physics and Astronomy · #Condensed matter physics #Entropy (arrow of time) #Hubbard model #Magnetic and transport properties of perovskites and related materials #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Specific heat #Spin (aerodynamics) #Thermodynamics #cond-mat.str-el #physics.comp-ph
paper · pdf · doi:10.1103/physrevb.102.085102
published in Physical review. B./Physical review. B 102(8) (American Physical Society) · 19 pages, 11 figures
arxiv created 2020/04/01 · openalex publication_date 2020/08/03 · arxiv updated 2020/08/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
The Hund's coupling in multiorbital Hubbard systems induces spin freezing and associated Hund metal behavior. Using dynamical mean-field theory, we explore the effect of local moment formation, spin, and charge excitations on the entropy and specific heat of the three-orbital model. For fillings 2\ensuremath\lesssimn<3 and low temperature, we demonstrate a substantial enhancement of the entropy in the spin-frozen metal phase to values comparable to the half-filled Mott insulator. We also discuss the appearance of entropy plateaus and peaks in the specific heat associated with the activation of spin and charge fluctuations at high temperature. The temperature scale for charge excitations is almost independent of filling and given by \ensuremath≈0.2U, with U the intraorbital repulsion. Local spin excitations become relevant for filling n>1 and their characteristic temperature is proportional to the Hund coupling J, with a filling-dependent prefactor. The analysis of the specific heat in the atomic limit yields accurate predictions for these features in the strong-coupling regime.