Speaker
Description
We study the spin-$1/2$ Heisenberg antiferromagnet on a diamond-decorated honeycomb lattice and uncover a parameter regime in which the ground state corresponds to a dimer-tetramer crystal. In this regime, low-energy excitations are captured by an effective hard-dimer model on the honeycomb lattice with anisotropic activities. This effective model exhibits thermodynamic behavior consistent with Kasteleyn physics such as a sharp feature in the specific heat and quasi-long-range dimer correlations. Although the presence of monomers in the effective model precludes a rigorous proof of a finite-temperature phase transition [1], our large-scale simulations prove negligible monomer contribution in the relevant low-temperature regime indicating that the observed anomalous features stem from emergent dimer constraints enabling to approach Kasteleyn phase transition arbitrarily closely. These findings not only identify a concrete paradigmatic example of the quantum Heisenberg antiferromagnet realizing emergent Kasteleyn physics, but they open a route to uncover Kasteleyn signatures.
Acknowledgements
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 945380.
References
[1] O.J. Heilmann and E. H. Lieb, “Monomers and dimers,” Physical Review Letters, vol. 24, no. 25, pp. 1412–1414, June 1970. https://doi.org/10.1103/PhysRevLett.24.1412
