High pressure Ca-VI phase between 158-180 GPa: Stability, electronic structure and superconductivity

Abstract

We have performed ab initio calculations for new high-pressure phase of Ca-VI between 158-180 GPa. The study includes elastic parameters of mono- and poly-crystalline 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 in the entire pressure range and the calculated Tc (~25K) is maximum at ~172 GPa, where the transfer of charges from 4s to 3d may be thought to be completed.

8 pages, 4 figures; PACS number(s): 74.70.Ad, 62.20.de, 71.20.-b, 74.20.Pq, 74.25.Kc, 74.62.Fj; Keywords: Calcium; High pressure; Electronic band structure; Phonon spectrum; Elastic constants; Superconductor

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• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Competing Phases, Strong Electron-Phonon Interaction and Superconductivity in Elemental Calcium under High Pressure

Cited by in corpus (3)

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• Characterization of the high-pressure superconductivity in the Pnma phase of calcium
• The superconducting phase of Calcium under the pressure at 200 GPa: the strong-coupling description