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Thermodynamic parameters of Zr superconductor at ω – β structural phase transition
Author(s) -
Szczȩśniak R.,
Durajski A. P.,
Szczȩśniak D.
Publication year - 2016
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.201552287
Subject(s) - pseudopotential , condensed matter physics , superconductivity , phase transition , dimensionless quantity , coulomb , coupling parameter , electron , jump , materials science , transition point , thermodynamics , physics , quantum mechanics
Abstractauthoren In the present study, the thermodynamic parameters of the superconducting state in zirconium at the structural ω – β phase transition ( ∼ 30 GPa) have been calculated. It has been shown that the jump of the critical temperature ( T C ) from 4.2 to 11K corresponds to the jump of the Coulomb pseudopotential from 0.26 to 0.41 . Other thermodynamic quantities, such as the order parameter at zero Kelvin ( Δ ( 0 ) ), the specific heat jump ( Δ C ( T C ) ), and the thermodynamic critical field ( H C ( 0 ) ) also undergo the abrupt change. The dimensionless parameters: R Δ≡ 2 Δ ( 0 ) / k B T C , R C≡Δ C ( T C ) / C N ( T C ) , and R H ≡ T C C N ( T C ) / H C 2 ( 0 ) are equal to the following: R Δ ∈ { 3.62 , 4.27 } , R C ∈ { 1.63 , 2.01 } , and R H ∈ { 0.167 , 0.139 } , respectively. Additionally, the structural phase transition induces the strong variation of the ratio of the electron effective mass to the electron band mass: m e ★ / m e ∈ { 1.84 , 2.98 } . From the physical point of view, the increasing deviations of the superconducting parameters from the predictions of the BCS theory at the structural ω – β phase transition have tight relation with the corresponding behavior of the electron–phonon coupling.