A high pressure Ca-VI phase between 158 and 180 GPa: stability, electronic structure and superconductivity
M Aftabuzzaman1, A K M A Islam
1Department of Physics, Rajshahi University, Rajshahi-6205, Bangladesh.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|February 23, 2011
Abstract:
We have performed ab initio calculations for a new high pressure phase of Ca-VI between 158 and 180 GPa. The study includes elastic parameters of monocrystalline and polycrystalline aggregates, electronic band structure, lattice dynamics and superconductivity. The calculations show that the orthorhombic Pnma structure is mechanically and dynamically stable in the pressure range studied. The structure is superconducting over the entire pressure range and the calculated T(c) (24.7 K with μ* = 0.1) is maximum at 172 GPa, which is close to the experimentally observed value of 25 K at 161 GPa.
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