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Structural Effects on the Electronic Properties of TlCu 7– δ S 4 Investigated by Diffraction‐Resistance Measurements
Author(s) -
Engin T. Erinc,
Hull Steve,
Powell Anthony V.
Publication year - 2012
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201200296
Subject(s) - crystallography , diffraction , ternary operation , electron diffraction , anomaly (physics) , neutron diffraction , reflection (computer programming) , materials science , powder diffraction , tetrahedron , phase (matter) , chemistry , condensed matter physics , crystal structure , physics , optics , organic chemistry , computer science , programming language
The design and construction of a specialised sample cell for the simultaneous investigation of electron‐transport and structural properties by powder neutron diffraction in the temperature range1.5 ≤ T /K ≤ 300 is described. This cell has been used to investigate the structural origin of anomalies in the transport properties of the pseudo‐one‐dimensional ternary sulfide TlCu 7– δ S 4 ( δ = 0.15). The data reveal an anomaly in ρ ( T ) observed at 255 K, which is associated with a phase change involving a change in symmetry from I 4/ m to P 4/ n on cooling. This corresponds to a doubling of the crystallographic c axis and is evidenced by the splitting of a strong reflection at d = 2.28 Å and the appearance of additional peaks in the low‐temperature diffraction data. A lower temperature ρ ( T ) anomaly at 205 K is related to subtle structural distortions involving chains of edge‐shared Cu 4 tetrahedra.