Critical properties of a spin-(1/2 chain with competing interactions

Abstract

The crossover between 2kF and 4kF charge-density waves in an extended one-dimensional Hubbard model is studied in the U' limit by mapping onto a Heisenberg antiferromagnet with a competing second-neighbor Ising interaction. The phase diagram is obtained by a combination of field theory techniques and numerical solution of finite chains. Regions of staggered spin order (4kF site or bond order) and (2,2) spin order (2kF site order) are mapped out. Critical exponents in the algebraic phase are obtained. © 1988 The American Physical Society.