Quasi one dimensional charge density wave instabilities in the family of monophosphate tungsten bronzes: (PO₂)₄(WO₃)_2m

TY - JOUR

T1 - Quasi one dimensional charge density wave instabilities in the family of monophosphate tungsten bronzes

T2 - (PO2)4(WO3)2m

AU - Foury, P.

AU - Pouget, J. P.

AU - Teweldemedhin, Z. S.

AU - Wang, E.

AU - Greenblatt, M.

PY - 1993/4/5

Y1 - 1993/4/5

N2 - We present a X-ray diffuse scattering investigation of the members m=4,6,7 of a new series of tungsten bronzes (PO2)4(WO3)2m, which exhibit two-dimensional electronic properties. Suprisingly, at ambient temperature these materials show quasi-one-dimensional (1D) charge density wave (CDW) fluctuations, as proved by computer simulations of the X-ray patterns. These fluctuations can be associated with particular chains of WO6 octahedra, contributing to flat portions of the Fermi surface of these materials. In P4W12O44 these fluctuations condense into successive phase transitions at 120 K and 62K where the electrical resistivity shows giant anomalies. In P4W14O50 they condense at 189 K into a triply incommensurate and non-sinusoidal modulation exhibiting harmonics up to the 6th order. Below 47 K another triply incommensurate and non-sinusoidal modulation is stabilized. Different quasi-1D fluctuations are involved in the 80 K and 52 K CDW phase transitions of P4W8O32. The origin of these 1D CDW instabilities and their 3D ordering at the various phase transitions are discussed in the framework of nesting mechanisms of the Fermi surface of these bronzes.

AB - We present a X-ray diffuse scattering investigation of the members m=4,6,7 of a new series of tungsten bronzes (PO2)4(WO3)2m, which exhibit two-dimensional electronic properties. Suprisingly, at ambient temperature these materials show quasi-one-dimensional (1D) charge density wave (CDW) fluctuations, as proved by computer simulations of the X-ray patterns. These fluctuations can be associated with particular chains of WO6 octahedra, contributing to flat portions of the Fermi surface of these materials. In P4W12O44 these fluctuations condense into successive phase transitions at 120 K and 62K where the electrical resistivity shows giant anomalies. In P4W14O50 they condense at 189 K into a triply incommensurate and non-sinusoidal modulation exhibiting harmonics up to the 6th order. Below 47 K another triply incommensurate and non-sinusoidal modulation is stabilized. Different quasi-1D fluctuations are involved in the 80 K and 52 K CDW phase transitions of P4W8O32. The origin of these 1D CDW instabilities and their 3D ordering at the various phase transitions are discussed in the framework of nesting mechanisms of the Fermi surface of these bronzes.

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U2 - 10.1016/0379-6779(93)90005-H

DO - 10.1016/0379-6779(93)90005-H

M3 - Article

SN - 0379-6779

VL - 56

SP - 2605

EP - 2610

JO - Synthetic Metals

JF - Synthetic Metals

IS - 2-3

ER -