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Updated: May 3, 2026
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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
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Efficient charge pumping in graphene
B Abdollahipour1, R Mohammadkhani
1Faculty of Physics, University of Tabriz, Tabriz 51666-16471, Iran.
Summary
This study reveals graphene quantum pumps driven by vibrating barriers efficiently pump electrons. Evanescent modes contribute significantly at the Dirac point, leading to unique oscillatory current behavior with increasing carrier concentration.
Area of Science:
- Condensed matter physics
- Quantum transport phenomena
Background:
- Graphene exhibits unique electronic properties due to its Dirac cone band structure.
- Quantum pumps are devices that can transport charge carriers without a net voltage bias.
- Understanding quantum pumping in low-dimensional materials is crucial for future electronic devices.
Purpose of the Study:
- To investigate the performance of a graphene quantum pump driven by vibrating potential barriers.
- To analyze the role of evanescent modes in the pumping process, particularly near the Dirac point.
- To compare the efficiency of vibrating barriers with oscillating barriers in a graphene quantum pump.
Main Methods:
- Adiabatic driving of two thin potential barriers around their equilibrium positions.
- Theoretical analysis of pumped current in a graphene system with highly doped leads.
- Investigation of carrier concentration effects on pumped current.
Main Results:
- The pumped current per mode diverges at the Dirac point for highly doped leads due to enhanced evanescent mode contribution.
- The graphene pump exhibits oscillatory current behavior with an increasing amplitude as a function of carrier concentration.
- Vibrating barriers lead to more efficient operation compared to oscillating barriers in this graphene quantum pump.
Conclusions:
- Graphene quantum pumps with vibrating barriers offer efficient charge transport, particularly benefiting from evanescent modes near the Dirac point.
- The observed oscillatory behavior and increasing amplitude with carrier concentration present a distinct characteristic compared to traditional quantum pumps.
- This research highlights the potential of engineered potential barriers for optimizing quantum pumping in graphene-based systems.
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