Kalisky B, Aronov P, Koren G, Shaulov A, Yeshurun Y, Huebener R P
Department of Physics, Institute of Superconductivity, Bar-Ilan University, Ramat-Gan 52900, Israel.
Phys Rev Lett. 2006 Aug 11;97(6):067003. doi: 10.1103/PhysRevLett.97.067003. Epub 2006 Aug 8.
Measurements of the nonlinear flux-flow resistivity rho and the critical vortex velocity vphi* at high voltage bias close to the instability regime predicted by Larkin and Ovchinnikov (Z. Eksp. Teor. Fiz 68, 1915 (1975) [Sov. Phys. JETP 41, 960 (1976)]) are reported along the node and antinode directions of the d-wave order parameter in the a-b plane of epitaxial YBa2Cu3O7-delta films. In this pinning-free regime, rho and vphi* are found to be anisotropic with values in the node direction larger on average by 10% than in the antinode direction. The anisotropy of rho is almost independent of temperature and field. We attribute the observed results to the anisotropic quasiparticle distribution on the Fermi surface of YBa2Cu3O7-delta.
报道了在外延YBa2Cu3O7-δ薄膜a-b平面中，沿着d波序参量的节点和反节点方向，在接近Larkin和Ovchinnikov所预测的不稳定区域的高电压偏置下，对非线性磁通流电阻率ρ和临界涡旋速度vphi的测量结果。在这个无钉扎区域中，发现ρ和vphi是各向异性的，节点方向的值平均比反节点方向大10%。ρ的各向异性几乎与温度和磁场无关。我们将观察到的结果归因于YBa2Cu3O7-δ费米面的各向异性准粒子分布。
