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Time-Resolved Quasiparticle Dynamics in the Spin-Density-Wave State

Elbert E. M. Chia·Jian-Xin Zhu·H. J. Lee·Namjung Hur·N. O. Moreno·R. D. Averitt·J. L. Sarrao·A. J. Taylor
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Abstract

Time-resolved photoinduced reflectivity is measured in the spin-density-wave (SDW) phase using itinerant antiferromagnets UMGa$_{5}$ (M=Ni, Pt). For UNiGa$_{5}$ [$T_{N}$=85 K, $Q$=($π$,$π$,$π$)], the relaxation time $τ$ shows a sharp increase at $T_{N}$ consistent with the opening of a SDW gap. For UPtGa$_{5}$ [$T_{N}$=26 K, $Q$=(0,0,$π$)], no change in $τ$ is observed at $T_{N}$ or at the lowest temperatures. We attribute this to the absence of the SDW gap at the Fermi level, due to a different modulation vector $Q$, which leads to a gapless quasiparticle spectrum. Our results challenge the conventional wisdom that a SDW phase necessarily implies a SDW gap at the Fermi level.

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Elbert E. M. Chia, Jian-Xin Zhu, H. J. Lee, Namjung Hur, N. O. Moreno, R. D. Averitt, J. L. Sarrao, A. J. Taylor. 2006-10-12. Time-Resolved Quasiparticle Dynamics in the Spin-Density-Wave State. https://arxiv.org/abs/cond-mat/0610353

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