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Phase coherence of conduction electrons below the Kondo temperature

Gassem M. Alzoubi Norman O. Birge
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Abstract

We have measured the phase decoherence rate, $τ_ϕ^{-1}$ of conduction electrons in disordered Ag wires implanted with 2 and 10 parts per million Fe impurities, by means of the weak localization magnetoresistance. The Kondo temperature of Fe in Ag, $T_K \approx 4$ K, is in the ideal temperature range to study the progressive screening of the Fe spins as the temperature $T$ falls below $T_K$. The contribution to $τ_ϕ^{-1}$ from the Fe impurities is clearly visible over the temperature range 40 mK -- 10 K. Below $T_K$, $τ_ϕ^{-1}$ falls rapidly until $T/T_K \approx 0.1$, in agreement with recent theoretical calculations. At lower $T$, $τ_ϕ^{-1}$ deviates from theory with a flatter $T$-dependence. We speculate that this latter behavior is due to incomplete screening of the s=2 Fe impurities by the conduction electrons.

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Gassem M. Alzoubi Norman O. Birge. 2006-07-06. Phase coherence of conduction electrons below the Kondo temperature. https://doi.org/10.1103/physrevlett.97.226803

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