Si Q, Rabello S, Ingersent K, Smith J L
Department of Physics & Astronomy, Rice University, Houston, Texas 77251-1892, USA.
Nature. 2001 Oct 25;413(6858):804-8. doi: 10.1038/35101507.
When a metal undergoes a continuous quantum phase transition, non-Fermi-liquid behaviour arises near the critical point. All the low-energy degrees of freedom induced by quantum criticality are usually assumed to be spatially extended, corresponding to long-wavelength fluctuations of the order parameter. But this picture has been contradicted by the results of recent experiments on a prototype system: heavy fermion metals at a zero-temperature magnetic transition. In particular, neutron scattering from CeCu6-x Aux has revealed anomalous dynamics at atomic length scales, leading to much debate as to the fate of the local moments in the quantum-critical regime. Here we report our theoretical finding of a locally critical quantum phase transition in a model of heavy fermions. The dynamics at the critical point are in agreement with experiment. We propose local criticality to be a phenomenon of general relevance to strongly correlated metals.
当一种金属经历连续量子相变时，临界点附近会出现非费米液体行为。通常认为，由量子临界性诱导的所有低能自由度在空间上是扩展的，这对应于序参量的长波涨落。但最近在一个原型系统（零温磁转变下的重费米子金属）上的实验结果与这一图景相矛盾。特别是，对CeCu6-x Aux的中子散射揭示了原子尺度上的反常动力学，这引发了关于量子临界区域中局域磁矩命运的诸多争论。在此，我们报告在重费米子模型中局部临界量子相变的理论发现。临界点处的动力学与实验结果相符。我们提出局部临界性是一种与强关联金属普遍相关的现象。
