Direct evidence for hidden one-dimensional Fermi surface of hexagonalK0.25WO3

Abstract

The electronic structure of hexagonal potassium tungsten bronze K 0.25 WO 3 has been investigated by highresolution angle-resolved photoemission spectroscopy ͑ARPES͒. 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 ͑1D͒ 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.

Raman signatures of charge ordering inK0.3WO3

“…However, recent studies have revisited the interest in these bronzes using angle-resolved photoelectron spectroscopy ͑ARPES͒ and revealed many interesting electronic structure related properties. 13 Particularly ARPES on x = 0.25 samples revealed the presence of a hidden 1D Fermi surface in conjunction with FS nesting, which is typically observed in charge-density-wave materials. 13 The observation of superlattice reflection by powder neutron-diffraction 27 and electron diffraction 10 experiments indeed support the possibility of Fermi-surface nesting accompanied by a CDW formation.…”

“…13 Particularly ARPES on x = 0.25 samples revealed the presence of a hidden 1D Fermi surface in conjunction with FS nesting, which is typically observed in charge-density-wave materials. 13 The observation of superlattice reflection by powder neutron-diffraction 27 and electron diffraction 10 experiments indeed support the possibility of Fermi-surface nesting accompanied by a CDW formation. The FS nesting in only one particular direction ͓⌫͑M͔͒ for x = 0.25 revealed by ARPES suggests a weak FS instability.…”

“…For x = 0.25, the recent angle-resolved photoemission studies revealed the existence of a hidden one-dimensional ͑1D͒ Fermi surface ͑FS͒ nesting showing the possibility of a charge-density-wave ground state. 13 A detailed study of soft-lattice modes in metallic Na x WO 3 has been reported by Flynn. 14 However, experimental studies focusing upon the lattice dynamics are limited to the previous neutron studies by Sato et al Optical spectroscopic properties of these materials remain still unexplored.…”

Ordered and twinned structure in hexagonal-based potassium tungsten bronze nanosheets

“…A channel structure is formed by cornerlinked WO 6 octahedra, with K-atom sites within the channel fully occupied when x = 0.33 and partially occupied when x < 0.33 (Magné li, 1953;Dickens & Whittingham, 1968;Hussain et al, 1978;Magneli & Blomberg, 1951). Previous studies revealed that the electric transport properties are closely related to the proportion of K in K x WO 3 (Krause et al, 1985;Sato et al, 1983;Raj et al, 2008;Sagar et al, 2010). For instance, the superconducting transition temperature (T c ) exhibited a discontinuity at x = 0.25 (Cadwell et al, 1981).…”

Comment on "Direct evidence for hidden one-dimensional Fermi surface of hexagonal K0.25WO3"

“…Recently, Raj et al [7] have reported angleresolved photoemission spectroscopy (ARPES) and firstprinciples density functional theory (DFT) results concerning the FS of the hexagonal potassium tungsten bronze, K 0.25 WO 3 [8] (see Fig. 1(a)).…”