Anomalous compression and new high-pressure phases of vanadium sesquioxide, V sub(2)O sub(3)

We report results of a powder x-ray diffraction (XRD) study of vanadium sesquioxide, V sub(2)O sub(3), under pressurization in a neon pressure-transmitting medium up to 57 GPa. We have established a bulk modulus value for corundum-type V sub(2)O sub(3) of B sub(()) = 150 GPa at B' = 4. This bul...

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Bibliographic Details
Published in:Journal of physics. Condensed matter 2013-09, Vol.25 (38), p.1-9
Main Authors: Ovsyannikov, Sergey V, Trots, Dmytro M, Kurnosov, Alexander V, Morgenroth, Wolfgang, Liermann, Hanns-Peter, Dubrovinsky, Leonid
Format: Article
Language:English
Subjects:
Band structure of solids
Bulk modulus
Compressing
Condensed matter
Electronics
Phases
Sesquioxides
Vanadium
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Summary:We report results of a powder x-ray diffraction (XRD) study of vanadium sesquioxide, V sub(2)O sub(3), under pressurization in a neon pressure-transmitting medium up to 57 GPa. We have established a bulk modulus value for corundum-type V sub(2)O sub(3) of B sub(()) = 150 GPa at B' = 4. This bulk modulus value is the lowest among those known for the corundum-type-structured oxides, e.g. A sub(1)O sub(3), alpha -Fe sub(2)O sub(3), Cr sub(2)O sub(3), Ti sub(2)O sub(3), and alpha -Ga sub(2)O sub(3). We have proposed that this might be related to the difference in the electronic band structures: at room temperature V sub(2)O sub(3) is metallic, but the above corundum-structured sesquioxides are semiconducting or insulating. Around ~21-27 and ~50 GPa we registered changes in the XRD patterns that might be addressed to phase transitions. These transitions were sluggish upon room-temperature compression, and hence we additionally facilitated them by the laser heating of one sample. We have refined the XRD patterns of only the first high-pressure phase in an orthorhombic lattice of a Rh sub(2)O sub(3)(II)-type. Our findings significantly extend the knowledge of the P-T phase diagram of V sub(2)O sub(3) and advance the understanding of its properties. We speculate that the elastic properties of V sub(2)O sub(3) can be closely linked to its electronic band structure and, consequently, we propose that slightly doped V sub(2)O sub(3) (e.g. with Cr) could be a potential candidate for systems in which the bulk modulus value may be remarkably switched by moderate pressure or temperature.
ISSN:0953-8984
1361-648X
DOI:10.1088/0953-8984/25/38/385401