NMR response in quasi–one-dimensional spin- antiferromagnetsJ. Sirker1, 2 and N. Laflorencie3
1 Max-Planck-Institut für Festkörperforschung - Heisenbergstrasse 1, D-70569 Stuttgart, Germany, EU
2 Technische Universität Kaiserslautern, Fachbereich Physik - Erwin-Schrödinger-Str., D-67663 Germany, EU
3 Laboratoire de Physique des Solides, Université Paris-Sud - UMR-8502 CNRS - 91405 Orsay, France, EU
received 1 April 2009; accepted in final form 24 May 2009; published June 2009
published online 22 June 2009
Non-magnetic impurities break a quantum spin chain into finite segments and induce Friedel-like oscillations in the local susceptibility near the edges. The signature of these oscillations has been observed in Knight shift experiments on the high-temperature superconductor YBa2Cu3O6.5 and on the spin chain compound Sr2CuO3. Here we analytically calculate NMR spectra, compare with the available experimental data for Sr2CuO3, and show that the interchain coupling is responsible for the complicated and so far unexplained lineshape. Our results are based on a parameter-free formula for the local susceptibility of a finite spin chain obtained by bosonization which is checked by comparing with quantum Monte Carlo and density matrix renormalization group calculations.
75.10.Pq - Spin chain models.
76.60.-k - Nuclear magnetic resonance and relaxation.
11.10.Wx - Finite-temperature field theory.
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