Ground state of =1 zigzag spin-orbital chain

Onishi, Hiroaki  

We investigate ground-state properties of a -orbital Hubbard model on a zigzag chain, by exploiting numerical techniques. The electron number per site is set to be two, leading to a local =1 state. That is, the system is a Haldane system with active orbital degrees of freedom. We assume that the level is split into the () and () levels due to the tetragonal crystalline electric field effect. With varying the level splitting, we observe a quantum phase transition that accompanies the change of the orbital state. We will report the detailed ground-state phase diagram and discuss the spin and orbital states. We will also discuss possible relevance of the obtained results to real compounds such as CaVO.