Interplay of charge and spin fluctuations of strongly interacting electrons on the kagome lattice

Abstract

We study electrons hopping on a kagome lattice at third filling described by an extended Hubbard Hamiltonian with on-site and nearest-neighbour repulsions in the strongly correlated limit. As a consequence of the commensurate filling and the large interactions, each triangle has precisely two electrons in the effective low energy description, and these electrons form chains of different lengths. The effective Hamiltonian includes the ring exchange around the hexagons as well as the nearest-neighbor Heisenberg interaction. Using large scale exact diagonalization, we find that the effective model exhibits two different phases: If the charge fluctuations are small, the magnetic fluctuations confine the charges to short loops around hexagons, yielding a gapped charge ordered phase. When the charge fluctuations dominate, the system undergoes a quantum phase transition to a resonating plaquette phase with ordered spins and gapless spin excitations. We find that a peculiar conservation law is fulfilled: the electron in the chains can be divided into two sublattices, and this division is conserved by the ring exchange term.

12 pages, 13 figures, small modifications in the text and in the figures

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Cited by in corpus (19)

• Electronic correlations in the normal state of kagome superconductor KV${}_3$Sb${}_5$
• Interaction-Driven Spontaneous Quantum Hall Effect on Kagome Lattice
• Cluster Mott insulators and two Curie-Weiss regimes on an anisotropic Kagome lattice
• Emergent orbitals in the cluster Mott insulator on a breathing Kagome lattice
• Superconducting pairing symmetry in the kagome-lattice Hubbard model
• Quantum Anomalous Hall Insulator Stabilized By Competing Interactions
• Quantum spin liquid and cluster Mott insulator phases in the Mo${}_3$O${}_8$ magnets
• Interaction-driven fractional quantum Hall state of hard-core bosons on kagome lattice at one-third filling
• Complex magnetic and spatial symmetry breaking from correlations in kagome flat bands
• Dimensional reduction in quantum spin-1/2 system on a 1/7-depleted triangular lattice
• Quantum anomalous Hall state from spatially decaying interactions on the decorated honeycomb lattice
• Quantum Phases of Kagome Electron System with Half-Filled Flat Bands
• Clusterization transition between cluster Mott insulators on a breathing Kagomé lattice
• Multiorbital kinetic effects on charge ordering of frustrated electrons on the triangular lattice
• Emergent lattices with geometrical frustration in doped extended Hubbard models
• Symmetry-protected Dirac nodal lines and large spin Hall effect in ${\mathbf{V}}_6\mathbf{S}{\mathbf{b}}_4$ with kagome bilayer
• Unconventional spin transport in strongly correlated kagome systems
• Solvable models for 2+1D quantum critical points: Loop soups of 1+1D conformal field theories
• Classification of mass terms in kagome semimetals