Dresden 2020 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 56: Correlated Electrons: Quantum-Critical Phenomena
TT 56.8: Talk
Thursday, March 19, 2020, 11:30–11:45, HSZ 304
Emergent spin 1/2 chains at domain walls of Kekulé valence-bond solids — •Toshihiro Sato1, Martin Hohenadler1, Tarun Grover2, John McGreevy2, and Fakher F. Assaad1 — 1Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany — 2Department of Physics, University of California at San Diego, USA
Dirac fermions with dynamically generated anticommuting Z2 Kekulé valence-bond solid (KVBS) and SO(3) antiferromagnetic (AFM) mass terms allow for the generation of a topological θ-term in the low energy effective field theory. Such a topological term is at the origin of phase transitions beyond the Ginzburg-Landau paradigm: topological defects of one phase carry the charge of the other and proliferate at the transition. In the vicinity of criticality and in the KVBS phase, the θ-term implies that a domain wall of the Z2 order parameter harbours a spin 1/2 Heisenberg chain. Using pinning fields to stabilize the domain wall, we show that our auxiliary field quantum Monte Carlo simulations indeed support the emergence of spin-1/2 chain at the Z2 defect.