Direct evidence for hidden one-dimensional Fermi surface of hexagonal $K_{0.25}WO_3$

Abstract

The electronic structure of hexagonal potassium tungsten bronze $K_{0.25}WO_3$ has been investigated by high-resolution angle-resolved photoemission spectroscopy (ARPES). The experimentally determined band structure resolves the long-standing puzzles concerning the anomalous transport properties in this hexagonal bronze. We find that the ARPES-derived Fermi surface is the consequence of hidden one-dimensional (1D) bands, in good agreement with the calculated Fermi surface. These results indicate that the high-temperature anomaly in the electrical resistivity originates in the possible charge-density-wave formation associated with the hidden 1D Fermi surfaces