Theoretical constraints for the magnetic-dimer transition in two-dimensional spin models

Abstract

From general arguments, that are valid for spin models with sufficiently short-range interactions, we derive strong constraints on the excitation spectrum across a continuous phase transition at zero temperature between a magnetic and a dimerized phase, that breaks the translational symmetry. From the different symmetries of the two phases, it is possible to predict, at the quantum critical point, a branch of gapless excitations, not described by standard semi-classical approaches. By using these arguments, supported by intensive numerical calculations, we obtain a rather convincing evidence in favor of a first-order transition from the ferromagnetic to the dimerized phase in the two-dimensional spin-half model with four-spin ring-exchange interaction, recently introduced by A.W. Sandvik et al. [Phys. Rev. Lett. 89, 247201 (2002)].

arXiv comment7 pages and 5 figures

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Cited by in corpus (8)

• From an Antiferromagnet to a Valence Bond Solid: Evidence for a First Order Phase Transition
• Nearly deconfined spinon excitations in the square-lattice spin-1/2 Heisenberg antiferromagnet
• Dynamical Signature of Fractionalization at the Deconfined Quantum Critical Point
• Unconventional continuous phase transition in a three dimensional dimer model
• Level spectroscopy in a two-dimensional quantum magnet: Linearly dispersing spinons at the deconfined quantum critical point
• Dynamics of the quantum dimer model on the triangular lattice: Soft modes and local resonating valence-bond correlations
• Valence bond solid phases in a cubic antiferromagnet
• The quantum J_{1}-J_{1'}-J_{2} spin-1/2 Heisenberg antiferromagnet: A variational method study