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arXiv · 1905.12697

NMR relaxation in the spin-1 Heisenberg chain

Sylvain Capponi·Maxime Dupont·Anders W. Sandvik·Pinaki Sengupta
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Abstract

We consider the isotropic $S=1$ Heisenberg chain with a finite Haldane gap $Δ$ and use state-of-the-art numerical techniques to investigate its dynamical properties at finite temperature, focusing on the nuclear spin-lattice relaxation rate $1/T_1$ measured in nuclear magnetic resonance (NMR) experiments for instance. In particular, we analyze the contributions from modes with momenta close to $q\approx 0$ and $q\approx π$ as a function of temperature. At high-temperature, we observe spin diffusion with a non-trivial exponent. At low-temperature, we argue that a simple activated behavior $1/T_1 \propto\exp(-Δ/T)$ can only be observed at temperatures much smaller than the gap $Δ$.

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Sylvain Capponi, Maxime Dupont, Anders W. Sandvik, Pinaki Sengupta. 2019-09-18. NMR relaxation in the spin-1 Heisenberg chain. https://doi.org/10.1103/physrevb.100.094411

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