Theory of Charge Order and Heavy-Electron Formation in the Mixed-Valence Compound KNi${}_2$Se${}_2$

Abstract

The material KNi${}_2$Se${}_2$ has recently been shown to possess a number of striking physical properties, many of which are apparently related to the mixed valency of this system, in which there is on average one quasi-localized electron per every two Ni sites. Remarkably, the material exhibits a charge density wave (CDW) phase that disappears upon cooling, giving way to a low-temperature coherent phase characterized by an enhanced electron mass, reduced resistivity, and an enlarged unit cell free of structural distortion. Starting from an extended periodic Anderson model and using the slave-boson formulation, we develop a model for this system and study its properties within mean-field theory. We find a reentrant first-order transition from a CDW phase, in which the localized moments form singlet dimers, to a heavy Fermi liquid phase as temperature is lowered. The magnetic susceptibility is Pauli-like in both the high- and low-temperature regions, illustrating the lack of a single-ion Kondo regime such as that usually found in heavy-fermion materials.

arXiv comment4.5 pages, 4 figures. Published version

References in corpus (10)

• Superconductivity mediated by charge fluctuations in layered molecular crystals
• Kondo Breakdown as a Selective Mott Transition in the Anderson Lattice
• Roles of Critical Valence Fluctuations in Ce- and Yb-Based Heavy Fermion Metals
• Charge ordering and antiferromagnetic exchange in layered molecular crystals of the theta type
• Mixed-Valence-Driven Heavy-Fermion Behavior and Superconductivity in KNi${}_2$Se${}_2$
• Charge density wave fluctuations, heavy electrons, and superconductivity in KNi${}_2$S${}_2$
• Magnetic Susceptibility of the Orbitally Degenerate (J= 5/2) Periodic Anderson Model - Analysis on the Basis of the Fermi Liquid Theory
• Valence Instability of YbCu${}_2$Si${}_2$ through its quantum critical point
• Kondo Stripes in an Anderson-Heisenberg Model of Heavy Fermion Systems
• Preformed heavy-electrons at the Quantum Critical Point in heavy fermion compounds

Cited by in corpus (7)

• Superconductivity and Charge Density Wave in ZrTe${}_{3-x}$Se${}_x$
• Multiband Superconductivity of Heavy Electrons in TlNi2Se2 single crystal
• Nematicity driven by hybridization in iron-based superconductors
• Melting of charge order in the low-temperature state of an electronic ferroelectric
• Optical properties of TlNi2Se2: Observation of pseudogap formation
• Superconductivity and Disorder Effect in TlNi${}_2$Se${}_{2-x}$S${}_x$ crystals
• Superconducting Order from Disorder in 2H-TaSe${}_{2-x}$S${}_x$ (0$\le$x$\le$2)