Evolution of quantum criticality in CeNi9−xCuxGe4
Evolution of quantum criticality in CeNi9−xCuxGe4
复制标题
CeNi9−xCuxGe4 中量子临界性的演变
DOI：
10.1088/0953-8984/21/23/235604
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
H. Michor
中科院分区：
文献类型：
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作者：
L. Peyker;Christian Gold;Ernst;Wolfgang Scherer;J. Donath;P. Gegenwart;Franz Mayr;Tobias Unruh;Volker Eyert;Ernst Bauer;H. Michor
重费米子系统 CeNi9−xCuxGe4 (0≤x≤1) 的晶体结构、比热、热膨胀、磁化率和电阻率研究揭示了通过 Ni/Cu 取代从 CeNi9Ge4 的有效四重简并非磁性近藤基态（具有明显的非费米液体特征）到磁有序、有效的基态的连续调谐。 CeNi8CuGe4 中的双重简并基态，TN = 175 ± 5 mK。观察到 的量子临界行为 。迄今为止，CeNi9−xCuxGe4 代表了第一个系统，其中取代驱动的量子相变不仅与近藤效应和 RKKY 相互作用的相对强度的变化有关，而且还与有效晶体场基态简并性的减少有关。
Crystal structure, specific heat, thermal expansion, magnetic susceptibility and electrical resistivity studies of the heavy fermion system CeNi9−xCuxGe4 (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 CeNi9Ge4 (with pronounced non-Fermi-liquid features) towards a magnetically ordered, effectively twofold-degenerate ground state in CeNi8CuGe4 with TN = 175 ± 5 mK. Quantum critical behavior, , is observed for . Hitherto, CeNi9−xCuxGe4 represents the first system where a substitution-driven quantum phase transition is connected not only with changes of the relative strength of the Kondo effect and RKKY interaction, but also with a reduction of the effective crystal field ground state degeneracy.