Zero-temperature spin-wave spectrum of the critical two-layer {ital S}=1/2 antiferromagnet

Journal Article · Wed May 01 04:00:00 EDT 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.53.11309· OSTI ID:283872

Gelfand, M P ^[1]

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1. Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

Series expansions about the interlayer dimer limit are calculated to eighth order in the intralayer coupling for the {ital T}=0 antiferromagnetic susceptibility and elementary excitation spectrum of the two-layer, {ital S}=1/2, square lattice Heisenberg antiferromagnet. Extrapolations of the susceptibility and the gap series yield an estimate of the critical interlayer/intralayer coupling ratio {ital J}{sub 2}/{ital J}{sub 1}=2.54{plus_minus}0.02, in agreement with several previous numerical calculations. The spin-wave velocity at criticality is determined by an analysis of the excitation spectrum series: the result, {h_bar}{ital c}/{ital J}{sub 1}{ital a}=1.89{plus_minus}0.02, is very precise and consistent with other estimates based on numerical calculations at finite temperature. The critical spin-wave dispersion at general wave vectors is shown to deviate significantly from a uniformly renormalized mean-field spectrum. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 283872
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 17 Vol. 53; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ANTIFERROMAGNETISM
DIMERS
DISPERSION RELATIONS
HEISENBERG MODEL
LAYERS
MAGNETIC SUSCEPTIBILITY
PERTURBATION THEORY
SERIES EXPANSION
SPIN WAVES
TEMPERATURE ZERO K
VELOCITY