Re-Entrant Quantum Phase Transitions in Antiferromagnetic Spin-1 Ladders

Abstract

In response to recent attempts to construct higher-spin ladder materials from organic polyradicals, we study the ground-state properties of a wide class of antiferromagnetic spin-1 ladders. Employing various numerical tools, we reveal the rich phase diagram and correct a previous nonlinear-sigma-model prediction. A variational analysis interprets the phase competition well with particular emphasis on the re-entrant phase boundary as a function of the rung interaction.