Structural instabilities and superconductivity in the alkali tungsten bronzes

@inproceedings{Ngai1978StructuralIA,
  title={Structural instabilities and superconductivity in the alkali tungsten bronzes},
  author={K L Ngai and Thomas L. Reinecke},
  year={1978}
}
A model of local structural states (phases) in the superconducting TI phase of the nonstoichiometric alkali tungsten bronzes MxWO3 (M an alkali) is shown to be consistent with the dramatic increase of the superconducting transition temperature as x approaches the TII phase boundary value. This model also predicts the existence of (x dependent) anharmonicity and heat capacity anomalies and it is consistent with the fact that the cubic phase of NaxWO3 is nonsuperconducting.