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High‐Pressure Synthesis of Fully Occupied Tetragonal and Cubic Tungsten Bronze Oxides
Author(s) -
Ikeuchi Yuya,
Takatsu Hiroshi,
Tassel Cédric,
Goto Yoshihiro,
Murakami Taito,
Kageyama Hiroshi
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201701732
Subject(s) - tetragonal crystal system , tungsten , bronze , electrical resistivity and conductivity , condensed matter physics , materials science , phase diagram , superconductivity , fermi level , phase (matter) , crystallography , crystal structure , chemistry , physics , metallurgy , electron , organic chemistry , quantum mechanics
A high‐pressure reaction yielded the fully occupied tetragonal tungsten bronze K 3 W 5 O 15 (K 0.6 WO 3 ). The terminal phase shows an unusual transport property featuring slightly negative temperature‐dependence in resistivity (d ρ /d T <0) and a large Wilson ratio of R W =3.2. Such anomalous metallic behavior possibly arises from the low‐dimensional electronic structure with a van Hove singularity at the Fermi level and/or from enhanced magnetic fluctuations by geometrical frustration of the tungsten sublattice. The asymmetric nature of the tetragonal tungsten bronze K x WO 3 ‐K 0.6− y Ba y WO 3 phase diagram implies that superconductivity for x ≤0.45 originates from the lattice instability because of potassium deficiency. A cubic perovskite KWO 3 phase was also identified as a line phase—in marked contrast to Na x WO 3 and Li x WO 3 with varying quantities of x (<1). This study presents a versatile method by which the solubility limit of tungsten bronze oxides can be extended.