Mixed-Valence-Driven Heavy-Fermion Behavior and Superconductivity in KNi${}_2$Se${}_2$

Abstract

Based on specific heat and magnetoresistance measurements, we report that a "heavy" electronic state exists below $T\approx$ 20 K in KNi${}_2$Se${}_2$, with an increased carrier mobility and enhanced effective electronic band mass, $m$* = 6$m_b$ to 18$m_b$. This "heavy" state evolves into superconductivity at $T_c$ = 0.80(1) K. These properties resemble that of a many-body heavy-fermion state, which derives from the hybridization between localized magnetic states and conduction electrons. Yet, no evidence for localized magnetism or magnetic order is found in KNi${}_2$Se${}_2$ from magnetization measurements or neutron diffraction. Instead, neutron pair-distribution-function analysis reveals the presence of local charge-density-wave distortions that disappear on cooling, an effect opposite to what is typically observed, suggesting that the low-temperature electronic state of KNi${}_2$Se${}_2$ arises from cooperative Coulomb interactions and proximity to, but avoidance of, charge order.

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Cited by in corpus (25)

• Magnetic properties in layered (K, Rb and Cs)Co2Se2 with ThCr2Si2_type structure
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• Charge density wave fluctuations, heavy electrons, and superconductivity in KNi${}_2$S${}_2$
• Multiband Superconductivity of Heavy Electrons in TlNi2Se2 single crystal
• Frustrated Spin One On A Diamond Lattice
• Nematicity driven by hybridization in iron-based superconductors
• Multi-gap nodeless superconductivity in nickel chalcogenide TlNi2Se2
• Lattice dynamics of KNi2Se2
• Electronic tunability of the frustrated triangular-lattice cluster magnet LiZn${}_{2-x}$Mo${}_3$O${}_8$
• Camelback-shaped band reconciles heavy electron behavior with weak electronic Coulomb correlations in superconducting TlNi2Se2
• Superconductivity in a new layered nickel-selenide CsNi2Se2
• Insulating and metallic spin glass in K${}_x$Fe${}_{2-\delta -y}$Ni${}_y$Se${}_2$ (0.06 $\le$ $y$ $\le$ 1.44) single crystals
• Orbital-selective charge-density wave in TaTe${}_4$
• Field-induced transition of the magnetic ground state from A-type antiferromagnetic to ferromagnetic order in CsCo2Se2
• Correlation effects in the electronic structure of the Ni-based superconducting KNi2S2
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• The weak electronic correlations and absence of heavy Fermion state in KNi${}_2$Se${}_2$
• Optical properties of TlNi2Se2: Observation of pseudogap formation
• A Single-Crystal Neutron Diffraction Study on Magnetic Structure of CsCo2Se2
• Trends in structural, electronic properties, Fermi surface topology, and inter-atomic bonding in the series of ternary layered dichalcogenides KNi2S2, KNi2Se2, and KNi2Te2 from first principles calculations
• Superconductivity and Disorder Effect in TlNi${}_2$Se${}_{2-x}$S${}_x$ crystals
• Electronic properties and surface states of RbNi${}_2$Se${}_2$
• Single crystal growth and superconductivity in RbNi${}_2$Se${}_2$
• Unconventional superconductivity in the nickel-chalcogenide superconductor, TlNi${}_2$Se${}_2$
• Representational Analysis of Extended Disorder in Atomistic Ensembles Derived from Total Scattering Data