Magnetic instability at the surface of a d-wave superconductor

Different scenarios for the low-temperature splitting of the zero-energy pe ak in the local density of states at (1 1 0) surfaces of d(x2 - y2) -wave s uperconductors are compared with each other. For a pure dx(2) - y(2)-wave s uperconductor surface bound states generate a large density of states at th e Fermi level. This causes local instabilities which occur either towards a time reversal symmetry breaking superconducting state (s + id-type) or a m agnetic slate with staggered magnetic moments. We show that both types of a local symmetry breaking would lead to similar splittings of the zero-energ y peak. (C) 2000 Elsevier Science B.V. All rights reserved.