Holes as dipoles in a doped antiferromagnet and stripe instabilities

Article

关键词: 2-DIMENSIONAL HUBBARD-MODEL;    VALENCE-BOND STATE;    TRANSITION-METAL OXIDES;    LONG-RANGE INTERACTIONS;    SPIN-CHARGE SEPARATION;    MEAN-FIELD-THEORY;    T-J MODEL;    HEISENBERG-MODEL;    SQUARE LATTICE;    PHASE;   

DOI  :  10.1103/PhysRevB.67.115103

来源: SCIE

【 摘 要 】

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.

【 授权许可】

Free