Staircase of crystal phases of hard-core bosons on the Kagome lattice - Université Toulouse 3
Article Dans Une Revue Physical Review B: Condensed Matter and Materials Physics (1998-2015) Année : 2016

Staircase of crystal phases of hard-core bosons on the Kagome lattice

Résumé

We study the quantum phase diagram of a system of hard-core bosons on the Kagome lattice with nearest-neighbor repulsive interactions, for arbitrary densities, by means of the hierarchical mean field theory and exact diagonalization techniques. This system is isomorphic to the spin S=1/2 XXZ model in presence of an external magnetic field, a paradigmatic example of frustrated quantum magnetism. In the non-frustrated regime, we find two crystal phases at densities 1/3 and 2/3 that melt into a superfluid phase when increasing the hopping amplitude, in semi-quantitative agreement with quantum Monte Carlo computations. In the frustrated regime and away from half-filling, we find a series of plateaux with densities commensurate with powers of 1/3. The broader density plateaux (at densities 1/3 and 2/3) are remnants of the classical degeneracy in the Ising limit. For densities near half-filling, this staircase of crystal phases melts into a superfluid, which displays finite chiral currents when computed with clusters having an odd number of sites. Both the staircase of crystal phases and the superfluid phase prevail in the non-interacting limit, suggesting that the lowest dispersionless single-particle band may be at the root of this phenomenon
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Dates et versions

hal-01380960 , version 1 (06-01-2025)

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Daniel Huerga, Sylvain Capponi, Jorge Dukelsky, Gerardo Ortiz. Staircase of crystal phases of hard-core bosons on the Kagome lattice. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2016, 94 (16), pp.165124. ⟨10.1103/PhysRevB.94.165124⟩. ⟨hal-01380960⟩
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