Possible realization of the exciton Bose liquid phase in a hard-core boson model with ring-only exchange interactions

Tiamhock Tay, Olexei I. Motrunich
2011 Physical Review B  
We investigate a hard-core boson model with ring-only exchanges on a square lattice, where a K_1 term acts on 1×1 plaquettes and a K_2 term acts on 1×2 and 2×1 plaquettes, with a goal of realizing a novel Exciton Bose Liquid (EBL) phase first proposed by Paramekanti, et al [Phys. Rev. B 66, 054526 (2002)]. We construct Jastrow-type variational wave functions for the EBL, study their formal properties, and then use them as seeds for a projective Quantum Monte Carlo study. Using Green's Function
more » ... onte Carlo, we obtain an unbiased phase diagram which at half-filling reveals CDW for small K_2, valence bond solid for intermediate K_2, and possibly for large K_2 the EBL phase. Away from half-filling, the EBL phase is present for intermediate K_2 and remains stable for a range of densities below 1/2 before phase separation occurs at lower densities.
doi:10.1103/physrevb.83.205107 fatcat:5oh4z4l46na6zp7uwd5idad4ee