| Recent experiments on several Yb-based heavy fermion compounds revealed non-Fermi liquid behavior in a finite zero-temperature region in the magnetic field- or pressure-tuned phase diagram. While the canonical view of heavy fermion quantum criticality assumes that the transition from magnetically ordered to heavy Fermi liquid takes place via a single quantum critical point, these observations raise the possibility that our underlying scenario for heavy fermion quantum criticality may need to be changed. For the case of Ge-doped YbRh2Si2 we advance arguments that the zero temperature non-Fermi liquid region is a new metallic Quantum Critical State and discuss its physical properties. |
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