Magnetic phase diagram and magnetic pairing in dopedLa2CuO4

Abstract

We discuss the temperature-concentration phase diagram of doped ${\mathrm{La}}_2$ ${\mathrm{CuO}}_4$. The addition of holes introduces a local ferromagnetic exchange coupling between Cu spins. The resulting frustration destroys the 3D Néel state characterizing pure ${\mathrm{La}}_2$ ${\mathrm{CuO}}_4$, and generates a new 3D spin-glass phase. In the paramagnetic phase, strongly correlated Cu spins in the planes are canted by the holes, yielding an oscillating dipole-dipole attraction between holes. The possible relevance to superconductivity is discussed.