Regensburg 1998 – scientific programme
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TT: Tiefe Temperaturen
TT 17: Theorie der Supraleitung
TT 17.6: Talk
Thursday, March 26, 1998, 12:00–12:30, H 18
Charge and Spin Structures of a dx2 − y2 Superconductor in the Proximity of an Antiferromagnetic Mott Insulator. — •F.F. Assaad1, M. Imada2, and D.J. Scalapino3 — 1Institut f"ur Theoretische Physik III, Universit"at Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart — 2ISSP, University of Tokyo — 3Depart. of Physics, UCSB
To the Hubbard model on a square lattice we add an interaction, W, which depends upon the square of a near-neighbor hopping. We use zero temperature quantum Monte Carlo simulations on lattice sizes up to 16 × 16, to show that at half-filling and constant value of the Hubbard repulsion, the interaction W triggers a quantum transition between an antiferromagnetic Mott insulator and a dx2 −y2 superconductor. We give numerical evidence for the occurrence of a finite temperature Kosterlitz-Thouless transition to the dx2 −y2 superconducting state. Above and below the Kosterlitz-Thouless transition temperature, TKT, we compute the one-electron density of states, N(ω), the spin relaxation rate 1/T1, as well as the imaginary and real part of the spin susceptibility χ(q→,ω). The spin dynamics are characterized by the vanishing of 1/T1 and divergence of Re χ( q→ = (π,π), ω = 0 ) in the low temperature limit. As TKT is approached N(ω) develops a pseudo-gap feature and below TKT Im χ( q→ = (π,π), ω ) shows a peak at finite frequency [1].
[1] F.F. Assaad, M. Imada and D.J. Scalapino, Phys. Rev. Lett. 77, 4592, (1996). ibid Phys. Rev. B in press.