Instabilities at  surfaces of superconductors
ETH-Hönggerberg - CH-8093 Zürich, Switzerland
2 Yukawa Institute for Theoretical Physics, Kyoto University - Kyoto 606-8502, Japan
Accepted: 16 February 2000
We compare different possible origins for the low-temperature splitting of the zero-energy peak in the local density of states at (110) surfaces of -wave superconductors. Using a tight-binding model with interactions in the Bogolyubov-de Gennes treatment, we discuss the instability of the superconductor against a current-carrying locally time-reversal symmetry-breaking phase ( s+id -wave) and, alternatively, a spin density wave-like state. The former (latter) is more likely to occur in a regime corresponding to the overdoped (underdoped) situation of high-temperture superconductors.
PACS: 74.50.+r – Proximity effects, weak links, tunneling phenomena, and Josephson effects / 75.30.Pd – Surface magnetism / 74.72.Bk – Y-based cuprates
© EDP Sciences, 2000