QFS 2016 Book of Abstracts

Abstracts

P2.19 Some applications of a framework comprising E F -incorporated equations for Δ 0 and T c and the corresponding number equations Malik Gulshan Jawaharlal Nehru University, Theory Group, School of Environmental Sciences, New Delhi 110067, India Augmenting the conventionally employed framework of BCS-BEC crossover physicse.g., 1 − 3 via inclusion of the equation for Tc and the corresponding number equation, replacing the BCS equations for Δ 0 and T c by the generalized BCS equations when dealing with non-elemental superconductors (SCs), and curtailing the limits of the number equations to avoid complex-valued solutions when EF k B θ D ( k B =Boltzmann constant; θ D =Debye temperature), we draw attention to recent work that dealt with (1) crossover physics without appeal to scattering length theory, 4 (2) the long-standing puzzle posed by SrT iO 3 , 5 (3) an explanation of hitherto unexplained features of La 2 CuO 4 , 6 and (4) heavy-fermion SCs. 7 [1 . ] D.M. Eagles, Phys. Rev. 186, 456 (1969) [2 . ] A.J. Leggett, in Modern Trends in the Theory of Condensed Matter (Springer- Verlag, Berlin, 1980) p. 13 [3 . ] R.M. Quick, C. Eseberg, M.de Llano, Phys. Rev. B 47, 11512 (1993) [4 . ] G.P. Malik, IJMPB 28, 1450054 (2014) [5 . ] G.P. Malik, IJMPB 28, 1450238 (2014) [6 . ] G.P. Malik, V.S. Varma, World J. Condens. Matt. Phys. 5, 148 (2015) [7 . ] G.P. Malik, J. Mod. Phys. 6, 1233 (2015) P2.20 On the role of Fermi energy in determining properties of superconductors Malik Gulshan Jawaharlal nehru University, Theory Group, School of Environmental Sciences, New Delhi 110067, India Supplementing the E F -incorporated equations for Δ0 and T c ,1 which were recently employed to deal with SrTiO3, La2CuO4, and heavy-fermion superconductors (SCs), by similar equations for the critical current density j 0 , we present new equations for the j 0 of elemental and composite SCs that depend solely on their following properties: E F , Debye temperature, gram-atomic volume, Sommerfeld constant, and a dimensionless construct where m* is the effective mass of superconducting electrons and P 0 their critical momentum. Calling attention to the recent treatment of several SCs in such a framework, 2 we present here an explanation of the { T c , j 0 } data on NbN films reported by Semenov et al. 3 [1 . ] G.P. Malik (Author), Superconductivity: A New Approach Based on the Bethe-Salpeter Equation in the Mean-Field Approximation, in: Series on Directions in Condensed Matter Physics – Volume 21, World Scientific,Singapore, 2016 [2 . ] G.P. Malik, “On the role of Fermi energy in determining properties of superconductors: A detailed comparative study of two elemental superconductors (Sn and Pb), a non-cuprates (MgB2) and three cuprates (YBCO, Bi-2212, and Tl-2212” (submitted) [3 . ] A. Semenov et al., Phys. Rev. B 80, 054510 (2009) 63