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One- and Two-Triplon Spectra of a Cuprate Ladder

S. Notbohm·P. Ribeiro·B. Lake·D. A. Tennant·K. P. Schmidt·G. S. Uhrig·C. Hess·R. Klingeler·G. Behr·B. Buechner·M. Reehuis·R. I. Bewley·C. D. Frost·P. Manuel·R. S. Eccleston
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Abstract

We have performed inelastic neutron scattering on the near ideal spin-ladder compound La4Sr10Cu24O41, which will serve as a model system for the investigation of doped ladders. A key feature in the analysis was the separation of one-triplon and two-triplon scattering contributions due to an antiphase rung modulation. This enabled extraction of the one-triplon dispersion which has a spin gap of 26.4+/-0.3 meV, and for the first time two-triplon scattering is clearly observed. The exchange constants are determined by fitting the data to be Jleg=186 meV and Jrung=124 meV along the leg and the rung respectively. In addition to the surprisingly large difference between Jleg and Jrung a substantial ring exchange of Jcyc=31 meV was confirmed.

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S. Notbohm, P. Ribeiro, B. Lake, D. A. Tennant, K. P. Schmidt, G. S. Uhrig, C. Hess, R. Klingeler, G. Behr, B. Buechner, M. Reehuis, R. I. Bewley, C. D. Frost, P. Manuel, R. S. Eccleston. 2006-08-07. One- and Two-Triplon Spectra of a Cuprate Ladder. https://doi.org/10.1103/physrevlett.98.027403

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