Impurity and Vortex States of high-Tc from the t-J model

Masao Ogata, Akihiro Himeda, Hiroki Tsuchiura +2 more

Kenji Tsutsui, Atsushi Toyama, Takami Tohyama +1 more

Hiroki Tsuchiura, Yukio Tanaka, Masao Ogata +1 more

The superconducting state around a well isolated nonmagnetic impurity in the high-Tc superconductors is studied using the two-dimensional t-J model. The spatial dependence of the order parameter and the local density of states are obtained from the numerical diagonalization of the Bogoliubov-de Gennes equation derived using the Gutzwiller approximation. We find a zero-energy peak in the local density of states around the impurity. Different from the previous results on a vortex or surfaces in the t-J model, the splitting of zero-energy peak is not found. The zero-energy states corresponding to the zero-energy peak is approximately localized around the impurity.

Masaru Kato, Kazumi Maki

Making use of the Bogoliubov-de Gennes equation, we study the quasi-particle spectrum and the vortex core structure of a single vortex in quasi 2D s-wave superconductors for small pFξ0, where pF is the Fermi momentum and ξ0 = vF/∆0 is the coherence length (¯h = 1). During our numerical calculation the particle number is conserved for each pFξ0. In particular, we find that there are only 1 or 2 bound states for pFξ0 = 1. Also, for pFξ0 = 1, the Kramer-Pesch effect ceases to exist at around T/Tc ≃ 0.3. There are renewed interests in vortex structure since the discovery of high Tc cuprate superconductors. It is possible that the superconductivity of high Tc cuprates can be characterized as d-wave superconductivity 1), 2) and is very close to the quantum

Hiroki Tsuchiura, Yukio Tanaka, Masao Ogata +1 more

Kazuhiro Kuboki, Hideki Tanaka, Manfred Sigrist