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Updated: Nov 7, 2025
11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
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Highly tunable junctions and non-local Josephson effect in magic-angle graphene tunnelling devices
Daniel Rodan-Legrain1, Yuan Cao2, Jeong Min Park3
1Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA. drodan@mit.edu.
Nature Nanotechnology
|May 4, 2021
Summary
Magic-angle twisted bilayer graphene (MATBG) devices demonstrate tunable quantum states. Researchers engineered Josephson junctions and transistors in MATBG, enabling versatile quantum device applications.
Area of Science:
- Condensed Matter Physics
- Materials Science
Background:
- Magic-angle twisted bilayer graphene (MATBG) is a tunable 2D material with diverse electronic phases.
- Controlling these phases electrostatically is key for novel quantum devices.
Purpose of the Study:
- To engineer Josephson junctions and transistors in MATBG using only electrostatic gates.
- To explore the quantum phenomena and device functionalities within a single MATBG platform.
Main Methods:
- Fabrication of multi-gated devices in MATBG for independent control of device components.
- Characterization of Josephson junctions, including their electrodynamics in a magnetic field.
- Implementation of edge tunnelling spectroscopy to probe superconducting phase energy spectra.
- Demonstration of single-electron transistor operation via Coulomb blockade in a double-barrier geometry.
Main Results:
- Successfully engineered purely 2D Josephson junctions and tunnelling transistors in MATBG.
- Observed non-local electrodynamics in MATBG Josephson junctions, consistent with Pearl theory.
- Measured the energy spectrum of MATBG in its superconducting phase using edge tunnelling spectroscopy.
- Demonstrated Coulomb blockade in a single-electron transistor configuration.
Conclusions:
- MATBG offers a versatile platform for creating complex quantum devices with electrostatic control.
- These devices show potential for applications in tunable superconducting qubits, on-chip circuits, and sensors.
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