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Locally critical quantum phase transitions in strongly correlated metals

Qimiao Si·Silvio Rabello·Kevin Ingersent·Lleweilun Smith
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Abstract

When a metal undergoes a continuous quantum phase transition, non-Fermi liquid behaviour arises near the critical point. It is standard to assume that all low-energy degrees of freedom induced by quantum criticality are spatially extended, corresponding to long-wavelength fluctuations of the order parameter. However, this picture has been contradicted by recent experiments on a prototype system: heavy fermion metals at a zero-temperature magnetic transition. In particular, neutron scattering from CeCu$_{6-x}$Au$_x$ 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 also argue that local criticality is a phenomenon of general relevance to strongly correlated metals, including doped Mott insulators.

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Qimiao Si, Silvio Rabello, Kevin Ingersent, Lleweilun Smith. 2001-08-30. Locally critical quantum phase transitions in strongly correlated metals. https://doi.org/10.1038/35101507

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