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Helical edge resistance introduced by charge puddles.
Jukka I Väyrynen1, Moshe Goldstein, Leonid I Glazman
1Department of Physics, Yale University, New Haven, Connecticut 06520, USA.
Physical Review Letters
|June 11, 2013
Summary
Electron puddles in 2D topological insulators cause inelastic backscattering, altering edge conductance. This study quantifies this effect and its dependence on temperature and doping.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Topological insulators possess unique conducting edge states protected by topology.
- Doping can create localized electron puddles, potentially disrupting edge state properties.
- Understanding these interactions is crucial for quantum device applications.
Purpose of the Study:
- To investigate the impact of electron puddles on the helical edge conductance of 2D topological insulators.
- To model the influence of a single electron puddle on edge backscattering.
- To analyze the collective effect of multiple puddles on edge resistance.
Main Methods:
- Modeling a single electron puddle as a quantum dot tunnel-coupled to the helical edge.
- Calculating the inelastic backscattering contribution to edge conductance.
- Extending the model to multiple puddles and analyzing temperature and doping dependencies.
Main Results:
- Electron puddles induce significant inelastic backscattering due to long electron dwelling times.
- A quantitative correction to the perfect edge conductance is derived.
- Helical edge resistance shows a dependence on temperature and doping level.
Conclusions:
- Electron puddles are a key factor affecting the transport properties of topological insulator edges.
- The developed model provides a framework for understanding experimental observations.
- Further research can guide the design of topological quantum devices by controlling puddle formation.
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