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Evidence for charge Kondo effect in superconducting Tl-doped PbTe.
Y Matsushita1, H Bluhm, T H Geballe
1Department of Materials Science and Engineering and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305-4045, USA.
Physical Review Letters
|May 21, 2005
Summary
This study reveals a charge Kondo effect in thallium-doped lead telluride crystals, evidenced by a resistivity upturn. This finding supports an electronic pairing mechanism for superconductivity in this material.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Phenomena
Background:
- Lead telluride (PbTe) is a promising thermoelectric material.
- Understanding superconductivity mechanisms in novel materials is crucial for technological advancements.
Purpose of the Study:
- Investigate the low-temperature electronic properties of Pb1-xTlxTe single crystals.
- Determine the role of thallium doping on resistivity and superconductivity.
Main Methods:
- Low-temperature thermodynamic and transport measurements.
- Analysis of resistivity upturn behavior with varying thallium concentrations.
- Examination of temperature and magnetic field dependence of transport properties.
Main Results:
- Observed a low-temperature resistivity upturn in Pb1-xTlxTe, scaling with thallium concentration.
- Characterized the upturn as a charge Kondo effect with a Kondo temperature of approximately 6 K.
- Identified degenerate thallium valence states differing by two electrons.
Conclusions:
- The charge Kondo effect provides evidence for an electronic pairing mechanism in Pb1-xTlxTe.
- This mechanism may explain the observed high superconducting transition temperatures (Tc).
- Thallium doping significantly influences the electronic behavior and superconducting properties of lead telluride.