Effect of a magnetic field on the specific heat jump of a superconducting alloy containing paramagnetic impurities with local states within the gap

Sihota, Bahadur; Nagi, A. D. S.

doi:10.1007/bf00683561

Cited by 5 publications

(2 citation statements)

References 17 publications

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“…where is normalized impurity concentration [30][31][32][33] , ln is Euler's constant, the (0) is the density of single-particle states at the Fermi level in the normal metal. The , , and (or, equivalently, , , and ) show the impurity effect on Green's functions.…”

Section: Methodsmentioning

confidence: 99%

“…The use of the SR model on the isotropic s-wave superconductors doped with the magnetic atoms specifies that the information on the potential scattering and the exchange interaction cannot be separately obtained; also, the energy of the bound states is a function of them 28 . The effect of the impurities on the anisotropic superconductors has been investigated by SR model; furthermore, Josephson current and several other properties of the superconducting alloy have been studied by SR approach [29][30][31][32][33] . Several valuable theoretical and experimental researches on the QPT in the superconductors in the presence of the magnetic impurity have done by using the lattice model, Bogoliubov-de-Gennes procedure and Majorana fermion approach [34][35][36][37][38][39][40][41] .…”

Section: Introductionmentioning

confidence: 99%

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Tuning of Quantum Entanglement of a Superconductor by Transition-Metal and Rare-Earth Impurity Effect and the Role of Potential Scattering on Quantum Phase Transition

Ebrahimian

Khosrojerdi

Afzali

2021

Preprint

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By considering transition-metal (Shiba-Rusinov model) and rare-earth metal impurities (Abrikosov-Gorkov theory) effect on a many-body system, i.e., a BCS s-wave superconductor, quantum bipartite entanglement of two electrons of the Cooper pairs in terms of the exchange interaction, J, the potential scattering, V(playing an important role, unexpectedly), and the distance of two electron spins of the Cooper pair is calculated at zero temperature by using two-electron spin-space density matrix (Werner state). In transition-metal case, we find new quantum phase transitions (QPTs). The changes of J, which causes to have localized excited state, V and the pairing interaction (via energy gap) lead to the displacement of the QPTs (interactions act in the same direction, however sometimes the pairing interaction causes the competition with other interactions), regardless of their effects on the value of concurrence. Determining the allowable values of all interactions by itself is not possible, due to the smallness of the perturbed Green’s functions (appearing in the density matrix). For non-magnetic and magnetic (rare-earth) impurity cases, concurrence versus the distance and collision times is discussed for all finite and infinite Debye frequency. The quantum correlation, instability of the system and what's more important QPT can be tuned by the impurity.

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Section: Methodsmentioning

confidence: 99%