arXiv:1902.10091 · Physical review. B./Physical review. B
Mixed-order transition and tricritical point associated with checkerboard supersolidity in the two-dimensional t2−V1 model
Amrita Ghosh, Satyaki Kar, Sudhakar Yarlagadda
Abstract
We use quantum Monte Carlo method employing stochastic-series-expansion technique to study the ground state properties of the ${t}_{2}\ensuremath{-}{V}_{1}$ model of hard-core bosons on a square lattice. We find that, away from half fillings, the minimal combination of nearest-neighbor repulsion ${V}_{1}$ and next-nearest-neighbor hopping ${t}_{2}$ may give rise to checkerboard supersolidity. The nature of the quantum phase transition, where the superfluid changes to a checkerboard supersolid, depends on the relative strength of ${V}_{1}/{t}_{2}$ and the average site occupancy. Interestingly, at the half filling, the model displays the extreme Thouless effect. As the filling is varied away from half filling, the model exhibits initially a mixed-order transition, next a tricritical point, and finally a second-order transition.