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Electron optics with p-n junctions in ballistic graphene
Shaowen Chen1, Zheng Han2, Mirza M Elahi3
1Department of Physics, Columbia University, New York, NY 10027, USA. Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA.
Science (New York, N.Y.)
|October 7, 2016
Summary
Electrons refract like light in graphene p-n junctions, showing positive and negative bending. This confirms Snell
Area of Science:
- Condensed matter physics
- Materials science
- Nanotechnology
Background:
- Electrons in semiconductors exhibit wave-like properties, including refraction at junctions.
- Graphene's unique electronic structure allows for highly transparent p-n junctions via electrostatic gating.
Purpose of the Study:
- To experimentally investigate electron refraction at graphene p-n junctions.
- To validate Snell's law for charge carriers in graphene.
- To understand the impact of junction width on carrier transmission.
Main Methods:
- Utilizing transverse magnetic focusing to track electron trajectories.
- Fabricating electrostatically defined graphene p-n junctions.
- Measuring angle-dependent transmission coefficients via resonant tunneling.
Main Results:
- Observed electron refraction consistent with Snell's law, including both positive and negative refraction.
- Demonstrated resonant transmission across the graphene p-n junction.
- Experimental data aligned with simulations, highlighting the importance of effective junction width.
Conclusions:
- Graphene p-n junctions exhibit electron optics phenomena analogous to classical optics.
- The study validates theoretical predictions and provides insights for designing graphene-based electronic devices.
- This work opens avenues for novel applications in electron optics and quantum electronics.
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