Based on an effective model of a doped antiferromagnetic Mott insulator, we show that a doped hole will induce a dipolelike spin configuration in a spin-ordered phase at low doping. The kinetic energy of doped holes is severely frustrated, and a hole-dipole object is actually localized or self-trapped in space. Without a balance from the kinetic energy, the long-range dipole-dipole interaction between doped holes will dominate the low-energy physics, leading to an inhomogeneity instability as the hole dipoles collapse into stripes. Both antiphase metallic stripes of quarter-filling and antiphase insulating stripes along a diagonal direction are discussed as composed of hole dipoles as elementary building blocks. Stripe melting and competing phases are also discussed.

• Received 22 October 2002

DOI:https://doi.org/10.1103/PhysRevB.67.115103