Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/80759
Title: Magnons in a two-dimensional transverse-field XXZ model
Authors: Kar, Satyaki
Wierschem, Keola
Sengupta, Pinaki
Keywords: DRNTU::Science::Physics
Magnetic Phase Transitions
Spin Waves
Issue Date: 2017
Source: Kar, S., Wierschem, K., & Sengupta, P. (2017). Magnons in a two-dimensional transverse-field XXZ model. Physical Review B, 96(4), 045126-. doi:10.1103/PhysRevB.96.045126
Series/Report no.: Physical Review B
Abstract: The XXZ model on a square lattice in the presence of a transverse magnetic field is studied within the spin-wave theory to investigate the resulting canted antiferromagnet. The small- and large-field regimes are probed separately both for easy-axis and easy-plane scenarios which reveal an unentangled factorized ground state at an intermediate value of the field. Goldstone modes are obtained for the field-free XY antiferromagnet as well as for the isotropic antiferromagnet with field up to its saturation value. Moreover, for an easy-plane anisotropy, we find that there exists a nonzero field, where magnon degeneracy appears as a result of restoration of a U(1) sublattice symmetry and that, across that field, there occurs a magnon band crossing. For completeness, we then obtain the system phase diagram for S=1/2 via large-scale quantum Monte Carlo simulations using the stochastic series expansion technique. Our numerical method is based on a quantization of spin along the direction of the applied magnetic field and does not suffer from a sign problem, unlike comparable algorithms based on a spin quantization along the axis of anisotropy. With this formalism, we are also able to obtain powder averages of the transverse and longitudinal magnetizations, which may be useful for understanding experimental measurements on polycrystalline samples.
URI: https://hdl.handle.net/10356/80759
http://hdl.handle.net/10220/46597
ISSN: 2469-9950
DOI: 10.1103/PhysRevB.96.045126
Schools: School of Physical and Mathematical Sciences 
Rights: © 2017 American Physical Society (APS). This paper was published in Physical Review B and is made available as an electronic reprint (preprint) with permission of American Physical Society (APS). The published version is available at: [http://dx.doi.org/10.1103/PhysRevB.96.045126]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:SPMS Journal Articles

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