Deconfined quantum critical point on the triangular lattice
Name
PhysRevB.97.195115.pdf
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396 KB
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Adobe PDF
Checksum (MD5)
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Author(s)
Jian, Chao-Ming
Thomson, Alex
Rasmussen, Alex
Bi, Zhen
Xu, Cenke
Date Issued
May 2018
Journal
Physical Review B
Publisher
American Physical Society
Citation
Jian, Chao-Ming et al. "Deconfined quantum critical point on the triangular lattice." Physical Review B 97, 19 (May 2018): 195115 © 2018 American Physical Society
Version
Final published version
Abstract
In this work we propose a theory for the deconfined quantum critical point (DQCP) for spin-1/2 systems on a triangular lattice, which is a direct unfine-tuned quantum phase transition between the standard “√3×√3” noncollinear antiferromagnetic order (or the so-called 120^{∘} state) and the “√12×√12” valence solid bond (VBS) order, both of which are very standard ordered phases often observed in numerical simulations. This transition is beyond the standard Landau-Ginzburg paradigm and is also fundamentally different from the original DQCP theory on the square lattice due to the very different structures of both the magnetic and VBS order on frustrated lattices. We first propose a topological term in the effective-field theory that captures the “intertwinement” between the √3×√3 antiferromagnetic order and the √12×√12 VBS order. Then using a controlled renormalization-group calculation, we demonstrate that an unfine-tuned direct continuous DQCP exists between the two ordered phases mentioned above. This DQCP is described by the N[subscript f]=4 quantum electrodynamics (QED) with an emergent PSU(4)=SU(4)/Z₄ symmetry only at the critical point. The aforementioned topological term is also naturally derived from the N[subscript f] = 4 QED. We also point out that physics around this DQCP is analogous to the boundary of a 3d bosonic symmetry- protected topological state with only on-site symmetries.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.1103/PhysRevB.97.195115
