1. Neutron diffraction studies of the negative thermal expansion in a layered indium selenide crystal
- Author
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P. E. Butorin, A. I. Dmitriev, Zakhar D. Kovalyuk, A. I. Beskrovnyĭ, V. I. Ivanov, G. V. Lashkarev, and V. M. Kaminskiĭ
- Subjects
Diffraction ,Materials science ,Neutron diffraction ,Atmospheric temperature range ,Condensed Matter Physics ,Molecular physics ,Thermal expansion ,Electronic, Optical and Magnetic Materials ,Crystal ,chemistry.chemical_compound ,chemistry ,Negative thermal expansion ,Selenide ,Single crystal - Abstract
The neutron diffraction patterns have been analyzed for a layered single crystal and a powder of the γ-polytype of indium selenide in the temperature range 10–300 K. In the temperature range 10–50 K, the excitation of bending vibrations due to the charge density waves changes the phonon spectrum and gives rise to a negative thermal expansion in the plane of layers, i.e., α‖c = −2.2 × 10−6 K−1, which is characteristic of two-dimensional structures. The average (over the range T = 50–300 K) coefficients of thermal expansion along the principal crystallographic directions have been calculated: \( \bar \alpha _{ \bot c} \) = 10.48 × 10−6 K−1 and \( \bar \alpha _{\parallel c} \) = 12.97 × 10−6 K−1, which agree with the X-ray diffraction data previously obtained by the authors at T = 290 K.
- Published
- 2009
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