Phase diagram of an extended quantum dimer model on the hexagonal lattice

TL;DR

This paper studies an extended quantum dimer model on the hexagonal lattice, revealing new crystalline phases and complex transition behavior, including potential fractal flux variations near the Rokhsar-Kivelson point.

Contribution

It introduces a novel quantum dimer model with additional potential terms and analyzes its phase diagram, uncovering new phases and transition phenomena.

Findings

Discovery of new crystalline phases

Identification of a cascade of flux transitions

Evidence for fractal ground-state flux variations

Abstract

We introduce a quantum dimer model on the hexagonal lattice that, in addition to the standard three-dimer kinetic and potential terms, includes a competing potential part counting dimer-free hexagons. The zero-temperature phase diagram is studied by means of quantum Monte Carlo simulations, supplemented by variational arguments. It reveals some new crystalline phases and a cascade of transitions with rapidly changing flux (tilt in the height language). We analyze perturbatively the vicinity of the Rokhsar-Kivelson point, showing that this model has the microscopic ingredients needed for the "devil's staircase" scenario [E. Fradkin et al., Phys. Rev. B 69, 224415 (2004)], and is therefore expected to produce fractal variations of the ground-state flux.