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arXiv · 0704.0506

Dimensional crossover of quantum critical behavior in CeCoIn$_5$

J. G. Donath·P. Gegenwart·F. Steglich·E. D. Bauer·J. L. Sarrao
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Abstract

The nature of quantum criticality in CeCoIn$_5$ is studied by low-temperature thermal expansion $α(T)$. At the field-induced quantum critical point at H=5 T a crossover scale $T^\star\approx 0.3$ K is observed, separating $α(T)/T\propto T^{-1}$ from a weaker $T^{-1/2}$ divergence. We ascribe this change to a crossover in the dimensionality of the critical fluctuations which may be coupled to a change from unconventional to conventional quantum criticality. Disorder, whose effect on quantum criticality is studied in CeCoIn$_{5-x}$Sn$_x$ ($0\leq x\leq 0.18$), shifts $T^\star$ towards higher temperatures.

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J. G. Donath, P. Gegenwart, F. Steglich, E. D. Bauer, J. L. Sarrao. 2008-02-05. Dimensional crossover of quantum critical behavior in CeCoIn$_5$. https://doi.org/10.1103/physrevlett.100.136401

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