title: Fractional quantum-Hall liquid spontaneously generated by strongly correlated t(2g) electrons.
abstract: For topologically nontrivial and very narrow bands, Coulomb repulsion between electrons has been predicted to give rise to a spontaneous fractional quantum-Hall (FQH) state in the absence of magnetic fields. Here we show that strongly correlated electrons in a t(2g)-orbital system on a triangular lattice self-organize into a spin-chiral magnetic ordering pattern that induces precisely the required topologically nontrivial and flat bands. This behavior is very robust and does not rely on fine-tuning. In order to go beyond mean field and to study the impact of longer-range interactions, we map the low-energy electronic states onto an effective one-band model. Exact diagonalization is then used to establish signatures of a spontaneous FQH state.
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, 01171 Dresden, Germany.
authors.forename: Jörn W F
authors.initials: JW
authors.lastname: Venderbos
authors.forename: Stefanos
authors.initials: S
authors.lastname: Kourtis
authors.forename: Jeroen
authors.initials: J
authors.lastname: van den Brink
authors.forename: Maria
authors.initials: M
authors.lastname: Daghofer