Regensburg 1998 – scientific programme
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TT: Tiefe Temperaturen
TT 17: Theorie der Supraleitung
TT 17.5: Invited Talk
Thursday, March 26, 1998, 11:30–12:00, H 18
Quasiparticles in the Vortex State of Dirty d-wave Superconductors — •Peter Hirschfeld — Department of Physics, University of Florida, z.Z. Institut f"ur Theorie der Kondensierten Materie, Universit"at Karlsruhe, 76128 Karlsruhe, Germany
I discuss the problem of the vortex contribution to thermal and transport properties of dirty d-wave superconductors. In the clean limit, Volovik has argued that the main contribution to the density of states in a d-wave superconductor arises from extended quasiparticle states which may be treated semiclassically, giving rise to a specific heat contribution δ C(H) ∼ H1/2. I show that the extended states continue to dominate the dirty limit, but lead to a H logH behavior at the lowest fields, Hc1 ≪ H ≪ Hc2. This crossover may explain recent discrepancies in specific heat measurements at low temperatures and fields in the cuprate superconductors. I further calculate the field dependence of thermal and microwave conductivities within the same model, and compare to recent experiments on UPt3 and the cuprates. These results are applicable to a regime where impurities limit the quasiparticle mean free path. I finally consider the more difficult problem of including vortex lattice disorder, necessary to provide a description of transport at higher fields and temperatures. eigentliche Text, genau einmal