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arXiv · cond-mat/9507083

Random Exchange Quantum Heisenberg Chains

A. Furusaki·M. Sigrist·E. Westerberg·P. A. Lee·K. B. Tanaka·N. Nagaosa
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Abstract

The one-dimensional quantum Heisenberg model with random $\pm J$ bonds is studied for $S=\frac{1}{2}$ and $S=1$. The specific heat and the zero-field susceptibility are calculated by using high-temperature series expansions and quantum transfer matrix method. The susceptibility shows a Curie-like temperature dependence at low temperatures as well as at high temperatures. The numerical results for the specific heat suggest that there are anomalously many low-lying excitations. The qualitative nature of these excitations is discussed based on the exact diagonalization of finite size systems.

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A. Furusaki, M. Sigrist, E. Westerberg, P. A. Lee, K. B. Tanaka, N. Nagaosa. 1995-07-20. Random Exchange Quantum Heisenberg Chains. https://doi.org/10.1103/physrevb.52.15930

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