title: Spin Bose-metal and valence bond solid phases in a spin-1/2 model with ring exchanges on a four-leg triangular ladder.
abstract: We study a spin-1/2 system with Heisenberg plus ring exchanges on a four-leg triangular ladder using the density matrix renormalization group and Gutzwiller variational wave functions. Near an isotropic lattice regime, for moderate to large ring exchanges we find a spin Bose-metal phase with a spinon Fermi sea consisting of three partially filled bands. Going away from the triangular towards the square lattice regime, we find a staggered dimer phase with dimers in the transverse direction, while for small ring exchanges the system is in a featureless rung phase. We also discuss parent states and a possible phase diagram in two dimensions.
authors.affiliation: Department of Physics, University of California, Santa Barbara, California 93106, USA.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Block
authors.forename: D N
authors.initials: DN
authors.lastname: Sheng
authors.forename: Olexei I
authors.initials: OI
authors.lastname: Motrunich
authors.forename: Matthew P A
authors.initials: MP
authors.lastname: Fisher