Researchers Yuri Fukaya, Keiji Yada, and Yukio Tanaka from the Department of Physics at Kyoto University have published a study exploring the unique properties of hybrid systems combining unconventional magnetic materials and conventional superconductors. Their work, titled “p-wave superconductivity and Josephson current in p-wave unconventional magnet/s-wave superconductor hybrid systems,” was published in the prestigious journal Physical Review Letters.
The team investigated the surface density of states in these hybrid systems, focusing on the interplay between the unconventional magnetic order and the superconducting state. They found that the quasiparticle energy dispersion in these systems exhibits a spin-triplet p_x-wave energy gap structure due to the noncollinear spin structure along the x-direction. This leads to the emergence of zero-energy flat bands at the [100] edge of the material.
Analyzing the pair amplitude at the [100] edge, the researchers discovered that odd-frequency spin-triplet even-parity pairing is induced in the presence of these zero-energy flat bands, while even-frequency spin-singlet even-parity pairing remains. This finding highlights the complex and novel pairing mechanisms that can arise in these hybrid systems.
Furthermore, the study demonstrated the Josephson current in superconducting junctions involving these hybrid systems. The researchers found that the current-phase relation shows a φ-junction in the high-transparency limit, while in the low-transparency limit, the Josephson current exhibits temperature dependence due to the coupling of spin-singlet even-parity pairings. This behavior is particularly notable because p-wave superconductivity is primarily realized both in the bulk and at the edge of the material.
The practical applications of this research for the energy sector are still under exploration. However, understanding and controlling the unique properties of these hybrid systems could potentially lead to the development of more efficient and novel superconducting devices. For instance, the ability to manipulate the Josephson current could be harnessed to create more advanced and energy-efficient superconducting electronics. The research was published in Physical Review Letters, volume 133, issue 23, article 236703 (2024).
This article is based on research available at arXiv.