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Incommensurate nodes in the energy spectrum of weakly coupled antiferromagnetic Heisenberg ladders

M. Azzouz·B. Dumoulin·A. Benyoussef
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Abstract

Heisenberg ladders are investigated using the bond-mean-field theory [M.Azzouz, Phys. Rev. B 48, 6136 (1993)]. The zero inter-ladder coupling energy gap, the uniform spin susceptibility and the nuclear magnetic resonance spin-relaxation rate are calculated as a function of temperature and magnetic field. For weakly coupled ladders, the energy spectrum vanishes at incommensurate wavevectors giving rise to nodes. As a consequence, the spin susceptibility becomes linear at low temperature. Our results for the single ladder successfully compare to experiments on SrCu_2O_3 and (VO)_2P_2O_7 materials and new predictions concerning the coupling to the magnetic field are made.

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M. Azzouz, B. Dumoulin, A. Benyoussef. 1996-11-06. Incommensurate nodes in the energy spectrum of weakly coupled antiferromagnetic Heisenberg ladders. https://doi.org/10.1103/physrevb.55.r11957

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