Quantum anomalous Hall state from spatially decaying interactions on the decorated honeycomb lattice

Abstract

Topological phases typically encode topology at the level of the single particle band structure. But a remarkable class of models shows that quantum anomalous Hall effects can be driven exclusively by interactions, while the parent noninteracting band structure is topologically trivial. Unfortunately, these models have so far relied on interactions that do not spatially decay and are therefore unphysical. We study a model of spinless fermions on a decorated honeycomb lattice. Using complementary methods, mean-field theory and exact diagonalization, we find a robust quantum anomalous Hall phase arising from spatially decaying interactions. Our finding indicates that the quantum anomalous Hall effect driven entirely by interactions is a surprisingly robust and realistic phenomenon.arXiv:1705.05829v3 [cond-mat.str-el]

Quantum anomalous Hall insulator stabilized by competing interactions

“…Recently, by considering not only V 1 but also furtherneighbor repulsive interactions such as second-and thirdneighbor interactions, numerical calculations have established a QAH phase in various lattice models of spinless fermions [41][42][43]. The QBT realized in the kagome-lattice and decorated-honeycomb-lattice models, however, host a flat valence band which leads to a lack of particle-hole symmetry, generally requires fine tuning to maintain the flatness, and non-generically enhances the effects of interactions.…”

Stabilizing Topological Superfluidity of Lattice Fermions

“…We use unrestricted Hartree-Fock theory to examine a minimal model of interacting spinless fermions on a lattice. Recent work shows that phase diagrams produced using this approximation compare well with exact diagonalization results when applied to models of this type [25,26]. We study the honeycomb lattice as a demonstration.…”

Multiple insulating phases due to the interplay of strong correlations and lattice geometry in a single-orbital Hubbard model

“…They consist of one or more cluster types, e.g., a molecule, linked to form a net [15,16]. Many decorated lattices are reported to have novel ground states [17][18][19][20][21][22][23][24][25].…”

“…This lattice is realized in materials such as the trinuclear organometallic compounds, e.g., Mo 3 S 7 (dmit) 3 [4], in organic molecular crystals [5], in iron (III) acetates [1], in cold fermionic atoms [27], and in MOFs [12][13][14]. There are a number of theoretical studies that predict exotic phases of matter on this lattice, such as the quantum spin Hall insulator [20], quantum anomalous Hall insulator [21][22][23], topological metals [23], valence bond solids (VBS) [28][29][30][31], and quantum spin liquids [32][33][34] with non-Abelian anyons [32]. Many of these phases require complicated spin-orbit or long-range Coulomb interactions in spinless models that may be difficult to realize in real materials.…”