Gap Symmetry and a Revival of Superconductivity in High Parallel Magnetic Fields in Q2D and Q1D Organic, High-Tc, and Sr2RuO4 Compounds

Author： Lebed A.G.

Publisher： Springer Publishing Company

ISSN： 0896-1107

Source： Journal of Superconductivity: Incorporating Novel Magnetism, Vol.12, Iss.3, 1999-06, pp. : 453-458

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Abstract

From the BCS theory, we derive an equation determining the upper critical field, H_c2(T), parallel to conducting planes of both layered Q2D and Q1D superconductors. It extends the quasiclassical Ginzburg–Landau–Abrikosov–Gor'kov (GLAG) and Lawrence–Doniach descriptions of H_c2(T) to the case of high magnetic fields where the quantum nature of an electron motion along open Fermi surfaces is important. This equation demonstrates two new phenomena: (1) a complete restoration of superconductivity at H ≃ H_c5 > H_c2(0) in the case of p-wave pairing of electrons; (2) a surviving of superconductivity at H_c2(0) < h="">< h*_p="" in="" the="" case="" of="" s(d)-wave="" pairing,="" where="" h*_p="" ≠="" h_p="" [here,="" h_c2(0)="" and="" h_p="" are="" the="" quasiclassical="" glag="" upper="" critical="" field="" and="" the="" paramagnetic="" clogston–chandrasekhar="" limiting="" field,="" correspondingly;="" h_c5="" and="" h*_p="" are="" defined="" in="" the="" text].="" our="" analysis="" of="" recent="" experimental="" data="" on="" (tmtsf)_2pf_6="" by="" i.="" j.="" lee="" et="" al.="" and="" m.="" j.="" naughton="" et="" al.="" shows="" that="" superconductivity="" significantly="" exceeds="" h*_p.="" this="" demonstrates="" a="" strong="" suppression="" of="" the="" pauli="" pair-breaking="" effects="" and="" may="" reflect="" a="" p-wave="" pairing="" of="" electrons.="" we="" propose="" to="" measure="" h_c2(t)="" in="" sr_2ruo_4="" (which="" is="" believed="" to="" be="" a="" p-wave="" superconductor)="" to="" prove="" a="" symmetry="" of="" a="" superconducting="" order="" parameter.="">