2016/05/31 by A. M. Tsvelik, Igor Zaliznyak, I. A. Zaliznyak
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Coupling (piping) #Cuprate #Ferromagnetism #Ground state #Heisenberg model #Lambda #Magnetic and transport properties of perovskites and related materials #Magnetic field #Magnon #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Spins #Superconductivity #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.94.075152
published as Phys. Rev. B 94, 075152 (2016) · 11 pages
arxiv created 2016/06/01 · openalex publication_date 2016/08/26 · arxiv updated 2016/08/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the low-energy sector of the Heisenberg necklace model. Using the field-theory methods, we estimate how the coupling of the electronic spins with the paramagnetic Kondo spins affects the overall spin dynamics and evaluate its dependence on a magnetic field. We are motivated by the experimental realizations of the spin-1/2 Heisenberg chains in SrCuO2 and Sr2CuO3 cuprates, which remain one-dimensional Luttinger liquids down to temperatures much lower than the in-chain exchange coupling J. We consider the perturbation of the energy spectrum caused by the interaction \ensuremathγ with nuclear spins (I=3/2) present on the same sites. We find that the resulting necklace model has a characteristic energy scale, \mathrm\ensuremathΛ\ensuremath∼J1/3(\ensuremathγI)2/3, at which the coupling between (nuclear) spins of the necklace and the spins of the Heisenberg chain becomes strong. This energy scale is insensitive to a magnetic field B. For \ensuremathμBB>\mathrm\ensuremathΛ we find two gapless bosonic modes that have different velocities, whose ratio at strong fields approaches a universal number, √(2)+1.