Single to multi quasiparticle excitations in the itinerant helical magnet CeRhIn5

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• Dr. Chris Stock, University of Edinburgh
• Friday 06 February 2015, 14:00-15:00
• Physics East 217.

If you have a question about this talk, please contact Elizabeth Blackburn.

The noninteracting quasiparticle description of excitations is fundamental to condensed matter physics and the understanding of low energy fluctuations. However, interacting quasiparticle states have recently been recognized as important in the understanding of anomalous phases. We use neutron scattering to directly measure the breakdown of the single quasiparticle description of the spin excitations in a helical itinerant heavy fermion magnet – CeRhIn5. CeRhIn5 is an itinerant magnet where the Ce^{3+} spins order in a simple helical phase. We investigate the spin excitations and observe sharp spin-waves parameterized by a nearest neighbor exchange J_{RKKY}=0.88 \pm 0.05 meV. At higher energies, the spin fluctuations are heavily damped where single quasiparticle excitations are replaced by a momentum and energy broadened continuum constrained by kinematics of energy and momentum conservation. The delicate energy balance between localized and itinerant characters results in the breakdown of the single quasiparticle picture in CeRhIn5.

This talk is part of the Condensed Matter Physics Seminars series.

This talk is included in these lists:

• Bham Talks
• Cond. Mat. seminar
• Condensed Matter Physics Seminars
• Physics East 217
• What's on in Physics?

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