Magnetism and topological phases in an interacting decorated honeycomb lattice with spin-orbit coupling

Abstract

We study the interplay between spin-orbit coupling (SOC) and Coulomb repulsion in a Hubbard model on a decorated honeycomb lattice which leads to a plethora of phases. While a quantum spin hall insulator is stable at weak Coulomb repulsion and moderate SOC, a semimetallic phase emerges at large SOC in a broad range of Coulomb repulsion. This semimetallic phase has topological properties not observed in conventional metals such as a finite, non-quantized spin Hall conductivity. At large Coulomb repulsion and negligible spin-orbit coupling, electronic correlations stabilize a resonance valence bond (RVB) spin liquid state in contrast to the classical antiferromagnetic state predicted by mean-field theory. Under sufficiently strong SOC, such RVB state is transformed into a magnetic insulator consisting on S~3/2 localized moments on a honeycomb lattice with antiferromagnetic order and topological features.

13 pages, 10 figures

References in corpus (6)

• Topological Insulators with Inversion Symmetry
• An exact chiral spin liquid with non-Abelian anyons
• Interaction-driven topological insulators on the kagome and the decorated honeycomb lattices
• Correlation effects in two-dimensional topological insulators
• Absence of magnetic order for the spin-half Heisenberg antiferromagnet on the star lattice
• Flat bands and nontrivial topological properties in an extended Lieb lattice

Cited by in corpus (3)

• Theory of nematic charge orders in kagome metals
• Unconventional superconductivity near a flat band in organic and organometallic materials
• Topological superconductivity from doping a triplet quantum spin liquid in a flat band system