1998/12/31 by J. Merino, J Merino, Ross H. McKenzie +5 · 4 citations
Materials Science · Physics and Astronomy · #Anisotropy #Antiferromagnetism #Ground state #Heisenberg model #Iron-based superconductors research #Magnetization #Magnon #Organic and Molecular Conductors Research #Physics of Superconductivity and Magnetism #Quantum #Quantum fluctuation #Quantum phase transition #cond-mat.str-el
paper · pdf · doi:10.1088/0953-8984/11/14/012
published as J. Phys.: Condens. Matter 11 (1999) 2965 · 10 pages, RevTeX + epsf, 5 figures Replaced with published version. Comparison to series expansions energies included
openalex publication_date 1999/01/01 · arxiv created 1999/04/22 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We consider the effect of quantum spin fluctuations on the ground-state properties of the Heisenberg antiferromagnet on an anisotropic triangular lattice using linear spin-wave (LSW) theory. This model should describe the magnetic properties of the insulating phase of the family of superconducting molecular crystals. The ground-state energy, the staggered magnetization, magnon excitation spectra, and spin-wave velocities are computed as functions of the ratio of the antiferromagnetic exchange between the second and first neighbours, . We find that near , i.e., in the region where the classical spin configuration changes from a Néel-ordered phase to a spiral phase, the staggered magnetization vanishes, suggesting the possibility of a quantum disordered state. In this region, the quantum correction to the magnetization is large but finite. This is in contrast to the case for the frustrated Heisenberg model on a square lattice, for which the quantum correction diverges logarithmically at the transition from the Néel to the collinear phase. For large , the model becomes a set of chains with frustrated interchain coupling. For , the quantum correction to the magnetization, within LSW theory, becomes comparable to the classical magnetization, suggesting the possibility of a quantum disordered state. We show that, in this regime, the quantum fluctuations are much larger than for a set of weakly coupled chains with non-frustrated interchain coupling.