d-Wave pairing symmetry in cuprate superconductors-fundamental implications and potential applications

A combination of conventional and phase-sensitive probes has firmly established the prevalence of d-wave pairing symmetry in the superconducting state of high-T-c cuprates. In this paper we first describe the basic ideas behind our tricrystal phase-sensitive pairing symmetry experiments, which we use the half-integer flux quantum effect as a definitive signature for d-wave pairing symmetry. We then argue that d-wave symmetry is universal in the cuprates, including as an example our recent results on the electron-doped high-T-c superconductors. We consider the implications of this universal d-wave pairing symmetry for understanding the origin of high-temperature superconductivity, and on potential applications. In particular, we discuss the possibility of using the half-integer flux quantum effect for all d-wave single qubits and qubit arrays. (C) 2002 Elsevier Science B.V. All rights reserved.