Supersolidity in the triangular lattice spin-1/2 XXZ model: A variational perspective

Dariush Heidarian; Arun Paramekanti

doi:10.1103/PhysRevLett.104.015301

paper

Supersolidity in the triangular lattice spin-1/2 XXZ model: A variational perspective

arXiv:0910.2203 · doi:10.1103/PhysRevLett.104.015301

Abstract

We study the spin-1/2 XXZ model on the triangular lattice with a nearest neighbor antiferromagnetic Ising coupling $J_{z} > 0$ and unfrustrated ( $J_{⊥} < 0$ ) or frustrated ( $J_{⊥} > 0$ ) kinetic terms in zero magnetic field. Incorporating long-range Jastrow correlations over a mean field spin state, we obtain the variational phase diagram of this model on large lattices for arbitrary $J_{z}$ and either sign of $J_{⊥}$ . For $J_{⊥} < 0$ , we find a $3 \times 3$ supersolid for $J_{z} /∣ J_{⊥} ∣ ≳ 4.7$ , in excellent agreement with quantum Monte Carlo data. For $J_{⊥} > 0$ , a distinct $3 \times 3$ supersolid is found to emerge for $J_{z} / J_{⊥} \geq 1$ . Both supersolids exhibit a spontaneous density deviation from half-filling. At $J_{z} / J_{⊥} = \infty$ , the crystalline order parameters of these two supersolids are nearly identical, consistent with exact results.

4 pages, 4 figures, 1 table, published version

Supersolidity in the triangular lattice spin-1/2 XXZ model: A variational perspective

Abstract

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