Josephson effect for superconductors lacking time-reversal and inversion symmetries

Area of Science:

• Condensed Matter Physics
• Superconductivity
• Materials Science

Background:

• Superconducting compounds lacking a center of inversion necessitate a p-wave admixture to the primary order parameter (d-wave or s-wave).
• Violation of time-reversal symmetry, alongside broken inversion symmetry, allows for invariants involving the order parameters and directed current.

Purpose of the Study:

• To investigate the impact of broken inversion and time-reversal symmetries on Josephson currents in unconventional superconductors.
• To explore the theoretical implications for heavy-fermion compounds and cuprates exhibiting these symmetry-breaking properties.

Main Methods:

• Theoretical analysis of superconducting order parameters in systems without inversion symmetry.
• Examination of Josephson current properties under conditions of broken time-reversal symmetry.

Main Results:

• A novel property of the Josephson current is identified for tunneling into s-wave superconductors with a parallel p-wave component.
• This phenomenon is relevant to specific heavy-fermion compounds like CePt(3)Si and the pseudogap phase of cuprates.

Conclusions:

• The interplay of broken inversion and time-reversal symmetries leads to unique Josephson current behaviors.
• These findings offer insights into the complex physics of non-centrosymmetric superconductors and their potential applications.