Structural phase transition and related electronic properties in quasi-one-dimensional (NbSe_{4})_{10}/_{3}I
| Autor: | J. Craig Bennett, Herman J. P. van Midden, Erik Zupanič, Sašo Šturm, Albert Prodan, Maciej Zubko, Joachim Kusz, H. Böhm, Grzegorz Dubin |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Diffraction
Phase transition Niobium Crystal structure Crystallography X-Ray Instability Phase Transition diffuse scattering Selenium Phase (matter) Materials Chemistry Perpendicular Wave vector Molecular Structure Condensed matter physics Chemistry Temperature Metals and Alloys charge density waves Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Condensed Matter::Strongly Correlated Electrons one-dimensional structures Crystallization Charge density wave Iodine |
| Popis: | The real crystal structure of the (NbSe4)(10/3)I 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)]. |
| Databáze: | OpenAIRE |
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