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Hard-Core Bosons on the Kagome Lattice: Valence-Bond Solids and Their Quantum Melting

2006; American Physical Society; Volume: 97; Issue: 14 Linguagem: Inglês

10.1103/physrevlett.97.147202

1092-0145

Sergei V. Isakov, Stefan Weßel, Roger G. Melko, K. Sengupta, Yong Baek Kim,

Advanced Condensed Matter Physics

Using large scale quantum Monte Carlo simulations and dual vortex theory, we analyze the ground state phase diagram of hard-core bosons on the kagome lattice with nearest-neighbor repulsion. In contrast with the case of a triangular lattice, no supersolid emerges for strong interactions. While a uniform superfluid prevails at half filling, two novel solid phases emerge at densities $\ensuremath{\rho}=1/3$ and $\ensuremath{\rho}=2/3$. These solids exhibit an only partial ordering of the bosonic density, allowing for local resonances on a subset of hexagons of the kagome lattice. We provide evidence for a weakly first-order phase transition at the quantum melting point between these solid phases and the superfluid.