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Controlling Andreev Bound States with the Magnetic Vector Potential.
Christian M Moehle1, Prasanna K Rout1, Nayan A Jainandunsing1
1QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GADelft, The Netherlands.
Nano Letters
|October 24, 2022
Summary
Tunneling spectroscopy probes Andreev bound states (ABSs) in Josephson junctions. We show the magnetic vector potential creates opposite phase differences at each end, enabling ABS localization estimation.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Superconductivity
Background:
- Tunneling spectroscopy is crucial for investigating Andreev bound states (ABSs) in semiconductor-superconductor hybrid systems.
- Planar Josephson junctions (JJs) in 2D electron gases offer a promising platform for topological superconductivity.
- Understanding ABS behavior in these JJs is key to controlling topological properties.
Purpose of the Study:
- To perform Andreev bound state (ABS) spectroscopy at both ends of planar Josephson junctions (JJs).
- To investigate the influence of the magnetic vector potential on the ABS energy spectrum.
- To correlate ABS spectroscopy results with the localized phase difference induced by the vector potential.
Main Methods:
- Utilized tunneling spectroscopy to measure the energy spectrum of ABSs in planar JJs.
- Applied magnetic vector potentials to induce local superconducting phase differences.
- Performed microscopic simulations to complement experimental findings and validate the model.
Main Results:
- Observed that the local superconducting phase difference induced by the vector potential is equal in magnitude and opposite in sign at the two ends of the JJs.
- Demonstrated agreement between experimental results and a theoretical model assuming localized ABSs near tunnel barriers.
- Showcased that the local phase difference can quantitatively estimate the spatial separation of ABSs.
Conclusions:
- The study confirms the localization of ABSs near tunnel barriers in planar JJs.
- The magnetic vector potential provides a tool to probe and manipulate the phase of localized ABSs.
- This work establishes a method for estimating the relative positions of ABSs within JJs using phase difference measurements.
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