Macroscopic Quantum Coherence of the Spin Triplet in the Spin-Ladder Compound Sr14Cu24O41

Emilio Lorenzo (1) , L. P. Regnault (2) , Cyrille Boullier (3) , Nicolas Martin (3) , A.H. Moudden (4) , S. Vanishri (5) , Christophe Marin (5) , A. Revcolevschi (6)

1 NEEL - MagSup - Magnétisme et Supraconductivité
2 SPSMS - UMR 9001 - Service de Physique Statistique, Magnétisme et Supraconductivité
3 MDN - Magnétisme et Diffusion Neutronique
4 LLB - UMR 12 - Laboratoire Léon Brillouin
5 IMAPEC - Instrumentation, Material and Correlated Electrons Physics
6 CHIMSOL - Laboratoire de Physico-Chimie de l'Etat Solide

We report the direct observation by inelastic neutron scattering experiments of a spin triplet of magnetic excitations in the response associated with the ladders in the composite cuprate Sr14Cu24O41. This appears as a peak at q_{Q1D}=\pi and energy \Delta_1=32.5 meV, and we conjecture that all the triplets making up this conspicuous peak have the same phase and therefore interpret it as the signature of the occurrence of quantum coherence along the ladder direction between entangled spin pairs. From the comparison with previous neutron and x-ray data, we conclude that the temperature evolution of this mode is driven by the crystallization of holes into a charge density wave in the ladder sublattice

Domaines: Electrons fortement corrélés [cond-mat.str-el]

Emilio Lorenzo, L. P. Regnault, Cyrille Boullier, Nicolas Martin, A.H. Moudden, et al.. Macroscopic Quantum Coherence of the Spin Triplet in the Spin-Ladder Compound Sr14Cu24O41. Physical Review Letters, 2010, 105, pp.097202. ⟨10.1103/PhysRevLett.105.097202⟩. ⟨hal-00976687⟩