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arXiv · 0812.3880

Direct Observation of Magnon Fractionalization in the Quantum Spin Ladder

B. Thielemann·Ch. Rüegg·H. M. Rønnow·A. M. Läuchli·J. -S. Caux·B. Normand·D. Biner·K. W. Krämer·H. -U. Güdel·J. Stahn·K. Habicht·K. Kiefer·M. Boehm·D. F. McMorrow·J. Mesot
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Abstract

We measure by inelastic neutron scattering the spin excitation spectra as a function of applied magnetic field in the quantum spin-ladder material (C5H12N)2CuBr4. Discrete magnon modes at low fields in the quantum disordered phase and at high fields in the saturated phase contrast sharply with a spinon continuum at intermediate fields characteristic of the Luttinger-liquid phase. By tuning the magnetic field, we drive the fractionalization of magnons into spinons and, in this deconfined regime, observe both commensurate and incommensurate continua.

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B. Thielemann, Ch. Rüegg, H. M. Rønnow, A. M. Läuchli, J. -S. Caux, B. Normand, D. Biner, K. W. Krämer, H. -U. Güdel, J. Stahn, K. Habicht, K. Kiefer, M. Boehm, D. F. McMorrow, J. Mesot. 2008-12-19. Direct Observation of Magnon Fractionalization in the Quantum Spin Ladder. https://doi.org/10.1103/physrevlett.102.107204

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