Spin Bose-Metal and Valence Bond Solid Phases in a Spin- 1/2 Model with Ring Exchanges on a Four-Leg Triangular Ladder
Matthew S. Block, D. N. Sheng, Olexei I. Motrunich +1 more
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.
arXiv:1009.1179•Physical Review Letters•Apr 12, 2011•76 citations