Anomalous angle dependence of superconducting diode effect in a mixed spin-orbit coupling system

Area of Science:

• Condensed matter physics
• Superconductivity
• Spintronics

Background:

• Noncentrosymmetric superconductors with strong spin-orbit coupling (SOC) can exhibit the superconducting diode effect (SDE).
• The SDE is characterized by helical superconductivity, where Cooper pairs exhibit a net momentum.
• External magnetic fields are known to induce SDE in certain superconducting systems.

Purpose of the Study:

• To investigate the intrinsic SDE in superconductors featuring both Rashba and Dresselhaus SOCs.
• To elucidate the influence of magnetic field direction on nonreciprocal helical superconductivity.
• To understand the relationship between magnetic field orientation and Cooper-pair momentum anisotropy.

Main Methods:

• Theoretical exploration of SDE in a superconductor model with combined Rashba and Dresselhaus SOCs.
• Numerical simulations to analyze the behavior of Cooper-pair momentum under varying in-plane magnetic field directions.
• Investigation of the resulting angle dependence of the SDE.

Main Results:

• The magnitude of the field-induced Cooper-pair momentum shows strong anisotropy with changes in the in-plane magnetic field direction.
• This momentum anisotropy leads to a complex, angle-dependent SDE.
• The direction of the magnetic field plays a crucial role in the observed nonreciprocity.

Conclusions:

• The study highlights the critical role of magnetic field direction in controlling SDE in mixed-SOC superconductors.
• The findings provide a pathway for experimental realization of SDE in systems with combined Rashba and Dresselhaus SOCs.
• This research offers insights into the fundamental mechanisms governing helical superconductivity and nonreciprocal transport.