Spin-glass behavior in the insulating phase of high-T_c superconductors

Numerical simulations for the Aharomy model are reported. Upon increased doping, the simulations show an antiferromagnetic, a spin-glass antiphase and a pure spin-glass phase. The pure spin glass is found to open a gap which might just make room for any other nonmagnetic mechanism of high-Tc superconductivity. © 1990.