Clean realization of the Hund physics near the Mott transition: $\mathrm{Ni}{\mathrm{S}}_2$ under pressure

Abstract

Strong correlation effects caused by Hund's coupling have been actively studied during the past decade. Hund's metal, strongly correlated while far from the Mott insulating limit, was studied as a representative example. However, recently, it was revealed that a typical Mott system also exhibits a sign of Hund physics by investigating the kink structure in the spectral function of $\mathrm{Ni}{\mathrm{S}}_{2-\mathrm{x}}\mathrm{S}{\mathrm{e}}_{\mathrm{x}}$. Therefore, to understand the Hund physics in a half-filled multi-orbital system near the metal-insulator transition, we studied pressure-induced metallic states of $\mathrm{Ni}{\mathrm{S}}_2$ by using density functional theory plus dynamical mean-field theory. Hund physics, responsible for suppressing local spin fluctuation, gives low-energy effective correlations, separated from Mott physics, which suppresses charge fluctuation at higher energy. This effect is prominent when $J$ becomes comparable to the quasiparticle kinetic energy, showing apparent scaling behavior of the kink position $E_{kink}\sim J\cdot Z$. We suggest that the Hund effect can also be observed in the optical conductivity as a non-Drude-like tail with $1/\omega$ frequency dependence and non-monotonic temperature evolution of the integrated optical spectral weight at a fixed frequency. Our study demonstrates the important role of Hund's coupling for electronic correlations even in a half-filled system.

arXiv comment10 pages, 5 figures with following supplementary material (7 pages, 5 figures)

References in corpus (23)

• Strong electronic correlations from Hund's coupling
• Kinetic frustration and the nature of the magnetic and paramagnetic states in iron pnictides and iron chalcogenides
• Dynamical Mean-Field Theory within the Full-Potential Methods: Electronic structure of Ce-115 materials
• Coherence-incoherence crossover in the normal state of iron-oxypnictides and importance of the Hund's rule coupling
• Janus-faced influence of the Hund's rule coupling in strongly correlated materials
• The coherence-incoherence crossover and the mass-renormalization puzzles in Sr2RuO4
• Kinks in the dispersion of strongly correlated electrons
• DMFT+NRG study of spin-orbital separation in a three-band Hund's metal
• Kondo resonance narrowing in d- and f-electron systems
• Non-Drude universal scaling laws for the optical response of local Fermi liquids
• Strongly correlated materials from a numerical renormalization group perspective: How the Fermi-liquid state of Sr${}_2$RuO${}_4$ emerges
• Hundness versus Mottness in a three-band Hubbard-Hund model: On the origin of strong correlations in Hund metals
• Optical Response of Sr${}_2$RuO${}_4$ Reveals Universal Fermi-liquid Scaling and Quasiparticles Beyond Landau Theory
• Transport properties of Metallic Ruthenates: a DFT+DMFT investigation
• Signatures of Mottness and Hundness in archetypal correlated metals
• Optical properties of the infinite-layer La${}_{1-x}$Sr${}_x$NiO${}_2$ and hidden Hund's physics
• Metal-insulator transition in NiS${}_{2-x}$Se${}_x$
• Electronic correlations and Hund's coupling effects in SrMoO${}_3$ revealed by photoemission spectroscopy
• Direct observation of the bandwidth control Mott transition in the NiS${}_{2-x}$Se${}_x$ multiband system
• Poor Man's Understanding of Kinks Originating from Strong Electronic Correlations
• Low-energy physics of three-orbital impurity model with Kanamori interaction
• Band Structure and Terahertz Optical Conductivity of Transition Metal Oxides: Theory and Application to CaRuO${}_3$
• Structural investigation of the insulator-metal transition in NiS${}_{2-x}$Se${}_x$ compounds

Cited by in corpus (2)

• Low-energy perspective on two-orbital Hund metals and the case of LaNiO2
• Impact of strong electronic correlations on altermagnets: the case of NiS2