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Kondo proximity effect: how does a metal penetrate into a Mott insulator?
R W Helmes1, T A Costi, A Rosch
1Institute for Theoretical Physics, University of Cologne, 50937 Cologne, Germany.
Physical Review Letters
|September 4, 2008
Summary
We studied metal-insulator interfaces using dynamical mean-field theory. The metal penetrates the Mott insulator via the Kondo effect, with quasiparticle weight decaying as 1/x^2 at criticality.
Area of Science:
- Condensed matter physics
- Materials science
Background:
- Mott insulators exhibit a metal-insulator transition.
- Heterostructures of metals and Mott insulators are technologically relevant.
- The Kondo effect describes magnetic impurity interactions with conduction electrons.
Purpose of the Study:
- Investigate the electronic properties at the interface of a metal and a paramagnetic Mott insulator.
- Analyze the scaling behavior of the metal-insulator interface near the Mott critical point.
- Determine the spatial decay of quasiparticle weight at the interface.
Main Methods:
- Dynamical mean-field theory (DMFT) adapted for inhomogeneous systems.
- Numerical renormalization group (NRG) employed as an impurity solver.
- Analysis of scaling properties near the critical point.
Main Results:
- Metal penetration into the Mott insulator occurs via the Kondo effect.
- At criticality, quasiparticle weight decays as a power law (1/x^2) with distance x from the metal.
- Numerical results confirm the power-law decay, with a very small prefactor.
Conclusions:
- The study provides insights into the electronic structure of metal-insulator interfaces in Mott systems.
- The Kondo effect plays a crucial role in mediating metal penetration.
- The observed power-law decay and small prefactor highlight unique interface properties near criticality.
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