title: Zigzag and Checkerboard Magnetic Patterns in Orbitally Directional Double-Exchange Systems.
abstract: We analyze a t(2g) double-exchange system where the orbital directionality of the itinerant degrees of freedom is a key dynamical feature that self-adjusts in response to doping and leads to a phase diagram dominated by two classes of ground states with zigzag and checkerboard patterns. The prevalence of distinct orderings is tied to the formation of orbital molecules that in one-dimensional paths make insulating zigzag states kinetically more favorable than metallic stripes, thus allowing for a novel doping-induced metal-to-insulator transition. We find that the basic mechanism that controls the magnetic competition is the breaking of orbital directionality through structural distortions, and highlight the consequences of the interorbital Coulomb interaction.
authors.affiliation: CNR-SPIN and Dipartimento di Fisica "E. R. Caianiello", Universitá di Salerno, IT-84084 Fisciano (SA), Italy.|Marian Smoluchowski Institute of Physics, Jagellonian University, Reymonta 4, 30-059 Kraków, Poland.
authors.forename: W
authors.initials: W
authors.lastname: Brzezicki
authors.affiliation: CNR-SPIN and Dipartimento di Fisica "E. R. Caianiello", Universitá di Salerno, IT-84084 Fisciano (SA), Italy.
authors.forename: C
authors.initials: C
authors.lastname: Noce
authors.affiliation: CNR-SPIN and Dipartimento di Fisica "E. R. Caianiello", Universitá di Salerno, IT-84084 Fisciano (SA), Italy.
authors.forename: A
authors.initials: A
authors.lastname: Romano
authors.affiliation: CNR-SPIN and Dipartimento di Fisica "E. R. Caianiello", Universitá di Salerno, IT-84084 Fisciano (SA), Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cuoco