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Pressure dependence of superconducting transition temperature of MgB 2 up to 8 GPa
Author(s) -
Ma R.,
Liu M.,
Wang Y. G.,
Yang Y. H.
Publication year - 2007
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200541322
Subject(s) - condensed matter physics , superconductivity , phonon , hydrostatic pressure , anisotropy , superconducting transition temperature , transition temperature , lattice (music) , chemistry , materials science , physics , thermodynamics , quantum mechanics , acoustics
The pressure dependence of electronic structure, phonon frequencies, electron–phonon coupling constant, and the superconducting transition temperature T c in MgB 2 are calculated via zone‐center frozen phonon modes calculations using the FP‐LAPW method. The calculations are performed from pressure dependent lattice parameters measured experimentally up to 8 GPa. Under quasi‐hydrostatic pressure, T c is found to decrease with an approximately quadratic dependence, deviating significantly from the linearity. It is shown that the pressure‐induced anisotropic change of lattice parameters, the increasing E 2g phonon frequency, and nonlinear electron–phonon coupling are three key factors of producing nonlinear T c ( P ) observed in MgB 2 . (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)