Acta Cryst. (2013). B69, 229-237 [ doi:10.1107/S2052519213010336 ]
Abstract: The real crystal structure of the (NbSe4)10/3I charge density wave (CDW) compound is studied by simulation of the X-ray diffuse scattering. The average structure of the low-temperature twinned phase is determined and the phase transition is attributed to the formation of a CDW. The diffuse streaking, present in X-ray diffraction patterns above and below the transition at T = 282 K, is shown to be a projection of diffuse concentric rings perpendicular to the c* direction. The simulated patterns, based on a mismatch model between infinite NbSe4 chains, correlated by I atoms, are in good accordance with the experimental patterns. In addition to the experiments, the electronic properties of the high- and the low-temperature phases are calculated with the extended Hückel tight-binding method. The Fermi surfaces of the average structures above and below the phase transition appear very similar. Their shapes support a nesting instability and a CDW formation. The weak incommensurate CDW satellites, present below the phase transition, are at 100 K properly described by a modulation wavevector q = [0.06 (1), 0, 0.55 (1)].
Keywords: one-dimensional structures; charge density waves; diffuse scattering.
Portable Document Format (PDF) file
To open or display or play some files, you may need to set your browser up to use the appropriate software. See the full list of file types for an explanation of the different file types and their related mime types and, where available links to sites from where the appropriate software may be obtained.
The download button will force most browsers to prompt for a file name to store the data on your hard disk.
Where possible, images are represented by thumbnails.
Copyright © International Union of Crystallography