Spin-orbit coupling induced enhancement of upper critical field in superconducting A15 single crystals

초록

Spin-orbit coupling (SOC) plays an important role in determining the properties of superconductors and is crucial for designing novel superconducting materials with improved characteristics, including high-performance superconducting wires and topological superconductors for quantum computing. In this study, we systematically investigate the role of SOC in modifying superconducting properties. To this end, A15-structured single crystals of Ti3Sb and Nb3Pt, which share identical crystal structures but exhibit significantly different SOC effects, were synthesized using the tetra-arc Czochralski method. A comparative analysis of these materials demonstrates that SOC has a substantial impact on the upper critical field (Hc2): the Nb3Pt single crystal, which has stronger SOC than Ti3Sb, shows a much higher Hc2(0) approximate to Hc2orb(0) compared to that of Ti3Sb single crystal, which is Hc2(0) approximate to 0.82Horb c2 (0). These results underscore the significance of SOC as a critical factor in the design and optimization of superconducting materials, highlighting its potential for advancing next-generation applications in high-performance superconducting technologies.

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