Low temperature properties of the triangular-lattice antiferromagnet: a bosonic spinon theory

Abstract

We study the low temperature properties of the triangular-lattice Heisenberg antiferromagnet with a mean field Schwinger spin-1/2 boson scheme that reproduces quantitatively the zero temperature energy spectrum derived previously using series expansions. By analyzing the spin-spin and the boson density-density dynamical structure factors, we identify the unphysical spin excitations that come from the relaxation of the local constraint on bosons. This allows us to reconstruct a free energy based on the physical excitations only, whose predictions for entropy and uniform susceptibility seem to be reliable within the temperature range $0< T <0.3J, which is difficult to access by other methods. The high values of entropy, also found in high temperature expansions studies, can be attributed to the roton-like narrowed dispersion at finite temperatures.

16 pages, 5 figures

References in corpus (6)

• Excitation spectra of the spin-1/2 triangular-lattice Heisenberg antiferromagnet
• Magnon Decay in Noncollinear Quantum Antiferromagnets
• Flat spin wave dispersion in a triangular antiferromagnet
• Symplectic N and time reversal in frustrated magnetism
• Quantum Phases of Trapped Ions in an Optical Lattice
• Variational study of J1-J2 Heisenberg model on Kagome lattice using projected Schwinger boson wave functions