Phase separation in thet-Jmodel

Abstract

It is shown that, for the t-J model, dilute holes in an antiferromagnet are unstable against phase separation into a hole-rich and a no-hole phase. When the spin-exchange interaction J exceeds a critical value $J_c$, the hole-rich phase has no electrons. It is proposed that for J slightly less than $J_c$ the hole-rich phase is a low-density superfluid of electron pairs. A brief discussion of phase separation in other related models is given.