THE ANNEALED POSITIONS OF FERROMAGNETIC BONDS DOPED INTO A 2D ANTIFERROMAGNET

We determine where a given concentration of ferromagnetic (FM) bonds d oped into a square lattice antiferromagnet must go to minimize the sys tem's total magnetic energy. We find i) an infinite degeneracy of grou nd-state arrangements of FM bonds that correspond to completely unfrus trated configurations for classical spins, and ii) this degeneracy is lifted when quantum fluctuations are included, and phase-separated gro und states, such as periodic arrays of stripes of FM bonds, are found. A discussion of the application of these ideas to doped cuprate high- T-c superconductors with annealed disorder is presented.