Category Archives: 2004

Critical Current of the Spin-Triplet Superconducting Phase in Sr2RuO4

There have been two different proposals for the spin-triplet order parameter of the superconducting phase in Sr2RuO4; an f-wave order parameter and the multigap model where some of the bands have the line node. In an effort to propose an experiment that can distinguish two cases, we study the behavior of the supercurrent and compute the critical current for these order parameters when the sample is a thin film with the thickness d ≪  where  is the coherence length. It is found that the supercurrent behaves very differently in two models. This will serve as a sharp test for the identification of the correct order parameter.

Hae-Young Kee1, Yong Baek Kim1, and K. Maki2
1Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
2Department of Physics, University of Southern California, Los Angeles, CA 90089

Supercurrent in Nodal Superconductors

In recent years, a number of nodal superconductors have been identified; d-wave superconductors in high Tc cuprates, CeCoIn5, and -(ET)2Cu(NCS)2, 2D f-wave superconductor in Sr2RuO4 and hybrid s+g-wave superconductor in YNi2B2C. In this work we conduct a theoretical study of nodal superconductors in the presence of supercurrent. For simplicity, we limit ourselves to d-wave and 2D f-wave superconductors. We compute the quasiparticle density of states and the temperature dependence of the depairing critical current in nodal superconductors, both of which are accessible experimentally.

 

Igor Khavkine1 , Hae-Young Kee1  and K. Maki2
1Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
2Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484

Spatial variation of d-density-wave order in the presence of impurities

Effect of finite density of nonmagnetic impurities on a coexisting phase of d-density-wave (DDW) order and d-wave-superconducting (DSC) order is studied using Bogoliubov-de Gennes (BdG) method. The spatial variation of the inhomogeneous DDW order due to impurities has a strong correlation with that of density, which is very different from that of DSC order. The length scale associated with DDW is of the order of a few lattice spacing, and the nontrivial inhomogeneities are shown to make DDW order much more robust to the  repulsive potential, while DSC order becomes very sensitive to them. The effect of disorder on the density of states is also discussed.

Amit Ghosal
Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada L8S 4M1
Hae-Young Kee
Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7