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Quasiparticle Interference as a Direct Experimental Probe of Bulk Odd-Frequency Superconducting Pairing
Debmalya Chakraborty1, Annica M Black-Schaffer1
1Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden.
Physical Review Letters
|December 23, 2022
Summary
Quasiparticle interference (QPI) reveals bulk odd-frequency superconducting pairing. This novel method uses bias asymmetry in QPI to detect this pairing in superconductors, regardless of its origin.
Area of Science:
- Condensed Matter Physics
- Superconductivity Research
- Experimental Physics
Background:
- Superconducting pairing typically occurs at even frequencies.
- Odd-frequency superconducting pairing is a less understood phenomenon.
- Quasiparticle interference (QPI) is a powerful probe for electronic structures.
Purpose of the Study:
- To demonstrate QPI as a direct experimental probe for bulk odd-frequency superconducting pairing.
- To characterize the influence of odd-frequency pairing on QPI.
- To identify a generic signature of odd-frequency pairing in experimental data.
Main Methods:
- Utilizing Fourier transform scanning tunneling microscopy and spectroscopy (FT-STM/S).
- Analyzing quasiparticle interference patterns in a conventional s-wave superconductor under a magnetic field.
- Investigating the bias dependence of QPI peaks.
Main Results:
- QPI patterns are shown to be sensitive to bulk odd-frequency superconducting pairing.
- The presence of odd-frequency pairing is confirmed to be essential for characterizing QPI peaks in the studied system.
- A distinct bias asymmetry in QPI is identified as a signature of odd-frequency pairing.
Conclusions:
- QPI serves as a direct experimental probe for bulk odd-frequency superconducting pairing.
- The observed bias asymmetry in QPI is a generic feature indicative of odd-frequency pairing.
- This finding opens new avenues for exploring unconventional superconductivity.
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