Regensburg 2004 – scientific programme

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TT: Tiefe Temperaturen

TT 8: Postersitzung I: Supraleitung

TT 8.41: Poster

Monday, March 8, 2004, 14:30–19:00, Poster A

Optical conductivity and approximate conservation laws in d-wave superconductors — •Philip Howell¹ and Achim Rosch² — ¹Institut für Theorie der Kondensierten Materie, Universität Karlsruhe, 76128 Karlsruhe — ²Institut für Theoretische Physik, Universität zu Köln, 50937 Köln

Recent measurements on high-temperature superconductors show that the optical conductivity depends strongly on temperature. It has been pointed out [1] that inelastic quasiparticle–quasiparticle scattering in a d-wave superconductor suffers kinematical constraints: momentum conservation leads to an ‘Umklapp gap’ and hence exponential behaviour of the conductivity. Here we argue that there are additional generalised momenta [2] which are almost conserved. The decay of the resulting slow modes determines the optical conductivity at low temperatures, and we investigate their influence via a memory matrix approach.

[1] M. B. Walker and M. F. Smith, Phys. Rev. B 61, 11285 (2000)

[2] A. Rosch and N. Andrei, Phys. Rev. Lett. 85, 1092 (2000)