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Quasiparticle Relaxation Across a Spin Gap in the Itinerant Antiferromagnet UNiGa5

Elbert E. M. Chia·H. J. Lee·Namjung Hur·E. D. Bauer·T. Durakiewicz·R. D. Averitt·J. L. Sarrao·A. J. Taylor
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Abstract

Ultrafast time-resolved photoinduced reflectivity is measured for the itinerant antiferromagnet UNiGa$_{5}$ ($T_{N} \approx$85 K) from room temperature to 10 K. The relaxation time $τ$ shows a sharp increase at $T_{N}$ consistent with the opening of a spin gap. In addition, the temperature dependence of $τ$ below $T_{N}$ is consistent with the opening of a spin gap leading to a quasiparticle recombination bottleneck as revealed by the Rothwarf-Taylor model. This contrasts with canonical heavy fermions such as CeCoIn$_{5}$ where the recombination bottleneck arises from the hybridization gap.

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Elbert E. M. Chia, H. J. Lee, Namjung Hur, E. D. Bauer, T. Durakiewicz, R. D. Averitt, J. L. Sarrao, A. J. Taylor. 2006-05-09. Quasiparticle Relaxation Across a Spin Gap in the Itinerant Antiferromagnet UNiGa5. https://doi.org/10.1103/physrevb.74.140409

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