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TT: Fachverband Tiefe Temperaturen

TT 19: Frustrated Magnets - Spin Liquids - Theory

TT 19.11: Talk

Monday, March 12, 2018, 17:45–18:00, H 3010

Looking at an antiferromagnet from a spin-liquid point of view — •Marc Daniel Schulz — TU Dortmund, Germany

The Z₂ topological phase in the quantum dimer model on the Kagome-lattice is a candidate for the description of the low-energy physics of the anti-ferromagnetic Heisenberg model on the same lattice. We study the extend of the topological phase by interpolating between the exactly solvable parent Hamiltonian of the topological phase and an effective low-energy description of the Heisenberg model in terms of a quantum-dimer Hamiltonian. Therefore, we perform a perturbative treatment of the low-energy excitations in the topological phase including free and interacting quasi-particles. We find a phase transition driven by the condensation of bound states formed of topological excitations. The condensed phase corresponds to a valence bond solid and is characterized by a spontaneously broken rotational symmetry and a unit cell containing six sites.