Multiple magnon modes in spin- 1 2 Heisenberg antiferromagnet on simple square lattice in strong magnetic field

We discuss spin-1/2 Heisenberg antiferromagnet on simple square lattice in magnetic field H using a recently proposed bond-operator technique. It is well known that magnetically ordered phases of quantum magnets are well described at least qualitatively by the conventional spin-wave theory that only...

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Bibliographic Details
Published in:Physical review. B 2020-07, Vol.102 (1), p.1, Article 014409
Main Author: Syromyatnikov, A. V.
Format: Article
Language:English
Subjects:
Anomalies
Antiferromagnetism
Computer simulation
Green's functions
Lattice vibration
Magnetic fields
Magnets
Magnons
Spin dynamics
Structure factor
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Summary:We discuss spin-1/2 Heisenberg antiferromagnet on simple square lattice in magnetic field H using a recently proposed bond-operator technique. It is well known that magnetically ordered phases of quantum magnets are well described at least qualitatively by the conventional spin-wave theory that only introduces quantum corrections into the classical solution of the problem. We observe that quantum fluctuations change drastically dynamical properties of the considered model at H close to its saturation value: the dynamical structure factor shows anomalies corresponding to Green's function poles which have no counterparts in the spin-wave theory. That is, quantum fluctuations produce multiple short-wavelength magnon modes not changing qualitatively the long-wavelength spin dynamics. Our results are in agreement with previous quantum Monte Carlo simulations and exact diagonalization of finite clusters.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.102.014409