Exploring the spin-orbital ground state of Ba3CuSb2O9

Abstract

Motivated by the absence of both spin freezing and a cooperative Jahn-Teller effect at the lowest measured temperatures, we study the ground state of Ba3CuSb2O9. We solve a general spin-orbital model on both the honeycomb and the decorated honeycomb lattice, revealing rich phase diagrams. The spin-orbital model on the honeycomb lattice contains an SU(4) point, where previous studies have shown the existence of a spin-orbital liquid with algebraically decaying correlations. For realistic parameters on the decorated honeycomb lattice, we find a phase that consists of clusters of nearest-neighbour spin singlets, which can be understood in terms of dimer coverings of an emergent square lattice. While the experimental situation is complicated by structural disorder, we show qualitative agreement between our theory and a range of experiments.

12 pages, 9 figures

References in corpus (4)

• Spin-orbital quantum liquid on the honeycomb lattice
• A Spin-Orbital Singlet and Quantum Critical Point on the Diamond Lattice: FeSc2S4
• Identification of an RVB liquid phase in a quantum dimer model with competing kinetic terms
• Doubly degenerate orbital system in honeycomb lattice: implication of orbital state in layered iron oxide

Cited by in corpus (6)

• Spin--orbital interaction for face-sharing octahedra: Realization of a highly symmetric SU(4) model
• Spin-Orbital Order Modified by Orbital Dilution in Transition Metal Oxides: From Spin Defects to Frustrated Spins Polarizing Host Orbitals
• Spin-orbital order in undoped manganite LaMnO3 at finite temperature
• Resonating Valence-Bond State in an Orbitally Degenerate Quantum Magnet with Dynamical Jahn-Teller Effect
• Green's function variational approach to orbital polarons in KCuF3
• Ground-state phase diagram of the SU($4$) Heisenberg model on a plaquette lattice