Phase-sensitive tetracrystal pairing-symmetry measurements and broken time-reversal symmetry states of high-Tc superconductors

Abstract

A detailed analysis of the symmetric tetracrystal geometry used in phase-sensitive pairing symmetry experiments on high-Tc superconductors is carried out for both bulk and surface time-reversal symmetry-breaking states, such as the d+id′ and d+is states. The results depend critically on the substrate geometry. In the general case, for the bulk d+id′ (or d+is) state, the measured flux quantization should in general not be too different from that obtained in the pure d-wave case, provided |d′|≪|d| (or |s|≪|d|). However, in one particular high-symmetry geometry, the d+id′ state gives results that allow it to be distinguished from the pure d and the d+is states. Results are also given for the cases where surface d+is or d+id′ states occur at a [110] surface of a bulk d-wave superconductor. Remarkably, in the highest-symmetry geometry, a number of the broken time-reversal symmetry states discussed above give flux-quantization conditions usually associated with states not having broken time-reversal symmetry.

Source-reported materials — not catalogue approval

Similar papers