Ground State of S = 1 Zigzag Spin–Orbital Chain

Abstract

We investigate ground-state properties of a t 2g -orbital Hubbard model on a zigzag chain relevant for CaV 2 O 4 , by exploiting numerical techniques such as Lanczos diagonalization and density-matrix renormalization group. Assuming a V 3+ ion, a local spin S =1 state is formed by two electrons in the t 2g orbitals. That is, the system is a Haldane system with active t 2g -orbital degrees of freedom. We observe orbital-state transitions, yielding a distinct spin system under the orbital-ordered background. We also discuss the orbital structure induced by open edges, originating in the spatial anisotropy of the t 2g orbitals.