High-pressure behavior of red mercuric iodide: in situ X-ray diffraction and optical absorption studies

We have investigated the behavior of red mercuric iodide (α-HgI 2) under high pressures using in situ X-ray diffraction and optical absorption techniques. Our experimental results indicate that the tetragonal→orthorhombic phase transformation, observed at 1.4 GPa, is accompanied by an abrupt increas...

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Bibliographic Details
Published in:Solid state communications 2004-08, Vol.131 (7), p.473-478
Main Authors: Karmakar, Sukanta, Sharma, Surinder M.
Format: Article
Language:English
Subjects:
A. Mercuric iodide
C. X-ray diffraction
D. Optical absorption
E. High pressure
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Summary:We have investigated the behavior of red mercuric iodide (α-HgI 2) under high pressures using in situ X-ray diffraction and optical absorption techniques. Our experimental results indicate that the tetragonal→orthorhombic phase transformation, observed at 1.4 GPa, is accompanied by an abrupt increase in the band gap while the nature of the gap does not change. However, across the orthorhombic→hexagonal phase transformation, observed at ∼7.2 GPa, the gap decreases discontinuously and changes from direct to indirect type. These studies suggest that HgI 2 may metallize at ∼40 GPa, if not prevented by any other structural change.
ISSN:0038-1098
1879-2766
DOI:10.1016/j.ssc.2004.05.005