摘要
The pairing symmetry of the superconducting order parameter contains key information about the pairing mechanism of the superconductor. For conventional superconductors, whose pairing is usually induced by the electron-phonon interaction, the pairing symmetry is s-wave, and the superconducting gap is fully open everywhere on the Fermi surface. For unconventional superconductors such as the cuprate and heavy fermion superconductors, other pairing symmetries may occur, leading to symmetry-mandated nodes in the superconducting order parameter.
