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arXiv · 0812.3309

Evolution of Quantum Criticality in CeNi_{9-x}Cu_xGe_4

L. Peyker·C. Gold·E. -W. Scheidt·W. Scherer·J. G. Donath·P. Gegenwart·F. Mayr·V. Eyert·E. Bauer·H. Michor
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Abstract

Crystal structure, specific heat, thermal expansion, magnetic susceptibility and electrical resistivity studies of the heavy fermion system CeNi_{9-x}Cu_xGe_4 (0 <= x <= 1) reveal a continuous tuning of the ground state by Ni/Cu substitution from an effectively fourfold degenerate non-magnetic Kondo ground state of CeNi_9Ge_4 (with pronounced non-Fermi-liquid features) towards a magnetically ordered, effectively twofold degenerate ground state in CeNi_8CuGe_4 with T_N = 175 +- 5 mK. Quantum critical behavior, C/T ~ χ~ -ln(T), is observed for x about 0.4. Hitherto, CeNi_{9-x}Cu_xGe_4 represents the first system where a substitution-driven quantum phase transition is connected not only with changes of the relative strength of Kondo effect and RKKY interaction, but also with a reduction of the effective crystal field ground state degeneracy.

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L. Peyker, C. Gold, E. -W. Scheidt, W. Scherer, J. G. Donath, P. Gegenwart, F. Mayr, V. Eyert, E. Bauer, H. Michor. 2008-12-17. Evolution of Quantum Criticality in CeNi_{9-x}Cu_xGe_4. https://doi.org/10.1088/0953-8984%2F21%2F23%2F235604

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