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Studies of Quantum Spin Ladders at T=0 and at High Temperatures by Series Expansions

J. Oitmaa·Rajiv R. P Singh·Zheng Weihong
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Abstract

We have carried out extensive series studies, at T=0 and at high temperatures, of 2-chain and 3-chain spin-half ladder systems with antiferromagnetic intrachain and both antiferromagnetic and ferromagnetic interchain couplings. Our results confirm the existence of a gap in the 2-chain Heisenberg ladders for all non-zero values of the interchain couplings. Complete dispersion relations for the spin-wave excitations are computed. For 3-chain systems, our results are consistent with a gapless spectrum. We also calculate the uniform magnetic susceptibility and specific heat as a function of temperature. We find that as $T\to 0$, for the 2-chain system the uniform susceptibility goes rapidly to zero, whereas for the 3-chain system it approaches a finite value. These results are compared in detail with previous studies of finite systems.

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J. Oitmaa, Rajiv R. P Singh, Zheng Weihong. 1996-02-09. Studies of Quantum Spin Ladders at T=0 and at High Temperatures by Series Expansions. https://doi.org/10.1103/physrevb.54.1009

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