NMR response in quasi–one-dimensional spin-\chem{\frac{1}{2}} antiferromagnets
Jesko Sirker, Nicolas Laflorencie
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 YBa 2 Cu 3 O 6.5 and on the spin chain compound Sr 2 CuO 3 . Here we analytically calculate NMR spectra, compare with the available experimental data for Sr 2 CuO 3 , 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.
arXiv:0811.2106•Europhysics Letters (EPL)•Jun 1, 2009•13 citations