title: Itinerant electron-driven chiral magnetic ordering and spontaneous quantum Hall effect in triangular lattice models.
abstract: We study the Kondo Lattice and the Hubbard models on a triangular lattice. We find that at the mean-field level, these rotationally invariant models naturally support a noncoplanar chiral magnetic ordering. It appears as a weak-coupling instability at the band filling factor 3/4 due to the perfect nesting of the itinerant electron Fermi surface. This ordering is a triangular-lattice counterpart of the collinear Neel ordering that occurs on the half-filled square lattice. While the long-range magnetic ordering is destroyed by thermal fluctuations, the chirality can persist up to a finite temperature, causing a spontaneous quantum Hall effect in the absence of any externally applied magnetic field.
authors.affiliation: Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: Ivar
authors.initials: I
authors.lastname: Martin
authors.forename: C D
authors.initials: CD
authors.lastname: Batista