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Tunable pseudogap Kondo effect and quantum phase transitions in Aharonov-Bohm interferometers
Luis G G V Dias da Silva1, Nancy Sandler, Pascal Simon
1Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. diasdasilval@ornl.gov
Physical Review Letters
|June 13, 2009
Summary
We demonstrate a controlled pseudogap Kondo effect in a quantum dot system. This reveals quantum phase transitions driven by magnetic flux and electron interactions.
Area of Science:
- Quantum physics
- Condensed matter physics
- Mesoscopic systems
Background:
- Aharonov-Bohm rings with quantum dots are key for studying quantum phenomena.
- The interplay of electron interactions and interference is crucial in nanoscale devices.
- Kondo effect and pseudogaps are fundamental concepts in condensed matter physics.
Purpose of the Study:
- To investigate the behavior of two quantum dots in an Aharonov-Bohm ring under magnetic flux.
- To explore the realization of the pseudogap Kondo effect in a controlled experimental setup.
- To analyze the signatures of quantum phase transitions between Kondo and non-Kondo states.
Main Methods:
- Modeling the system using an effective one-impurity Anderson model.
- Analyzing the energy- and flux-dependent density of states.
- Calculating conductance and transmission phase shifts.
Main Results:
- A vanishing density of states at the Fermi energy for specific magnetic flux values.
- Controlled realization of the pseudogap Kondo effect.
- Observation of nontrivial interplay between wave interference and electron interactions.
Conclusions:
- The system provides a platform for studying the pseudogap Kondo effect.
- Clear signatures of quantum phase transitions are observed.
- The findings offer insights into the complex behavior of interacting quantum systems.
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