Frustration in Coupled Rattler System: KOs2O6

Abstract

The phenomenon of frustration, which gives rise to many fascinating phenomena, is conventionally associated with the topology of non-bipartite lattices, where nearest-neighbor (nn) interactions and global connectivity compete in the lowering of energy. The issue of rattling atoms in spacious lattice sites is a separate occurrence that can also lead to a high density of low energy states (unusual low temperature thermodynamics) and to practical applications such as in improved thermoelectric materials. In this letter we address a unique situation where both phenomena arise: a four-fold single-site instability leads to rattling of cations on a diamond structure sublattice where nn interactions frustrate simple ordering of the displacements. The system deals with this coupling of rattling+frustration by commensurate ordering. Such a disorder-order transition may account for the second phase transition seen in KOs2O6 within the superconducting state, and the unusual low-energy dynamics and associated electron-phonon coupling can account for the qualitative differences in physical properties of KOs2O6 compared to RbOs2O6 and CsOs2O6, all of which have essentially identical average crystal and electronic structures.

5 pages, 3 figure

References in corpus (14)

• New Pyrochlore Oxide Superconductor RbOs2O6
• New beta-Pyrochlore Oxide Superconductor CsOs2O6
• Correlation Effects and Structural Dynamics in the $\beta$-Pyrochlore Superconductor KOs${}_2$O${}_6$
• Mass enhancement, correlations, and strong coupling superconductivity in the beta-pyrochlore KOs2O6
• Superconductivity in Geometrically Frustrated Pyrochlore RbOs2O6
• Second Anomaly in the Specific Heat of beta-Pyrochlore Oxide Superconductor KOs2O6
• Specific Heat of the beta-Pyrochlore Oxide Superconductors CsOs2O6 and RbOs2O6
• Pressure effects on the transition temperature and the magnetic field penetration depth in the pyrochlore superconductor RbOs_2O_6
• Possible Anisotropic Order Parameter in Pyrochlore Superconductor KOs${}_2$O${}_6$ Probed by Muon Spin Rotation
• Electronic structure properties and BCS superconductivity in beta-pyrochlore oxides: KOs_2O_6
• Evidence for s-wave superconductivity in the new beta-pyrochlore oxide RbOs2O6
• Erratum to Three Papers on the beta-Pyrochlore Oxide Superconductors
• Evidence for charged critical behavior in the pyrochlore superconductor RbOs2O6
• Large mass enhancement in RbOs2O6

Cited by in corpus (17)

• NMR relaxation and resistivity from rattling phonons in pyrochlore superconductors
• Rattling-Induced Superconductiviy in the Beta-Pyrochlore Oxides AOs2O6
• NMR Observation of Rattling Phonons in the Pyrochlore Superconductor KOs2O6
• Low-Temperature and High-Energy-Resolution Laser Photoemission Spectroscopy
• Effects of Rattling Phonons on the Quasiparticle Excitation and Dynamics in the Superconducting $\beta$-Pyrochlore KOs${}_2$O${}_6$
• Neutron Scattering Study of the Localized Mode in the beta-Pyrochlore Superconductors AOs2O6
• Superconducting Transition in the $\beta$-Pyrochlore AOs${}_2$O${}_6$ (A=Cs, Rb, K) under Pressure
• A Possible Phase Transition in beta-pyrochlore Compounds
• Vortex Redistribution below the First-Order Transition Temperature in the β-Pyrochlore Superconductor KOs_2O_6
• Scanning Tunneling Spectroscopy in the Superconducting State and Vortex Cores of the beta-pyrochlore KOs2O6
• Structural and Superconducting Properties of RbOs2O6 Single Crystals
• Green's function of fully anharmonic lattice vibration
• Superconductivity and Rattling under High Pressure in the beta-Pyrochlore Oxide RbOs2O6
• Anharmonicity in one-dimensional electron-phonon system
• Novel Rattling of K Atoms in Aluminium-Doped Defect Pyrochlore Tungstate
• Partial order in a frustrated Potts model
• Towards a Mechanism of Rattler Coupling in the β-Pyrochlores AOs2O6 (A = K, Rb, Cs)