Talk (non-conference) (Invited)

FZJ-2025-04467

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Towards Cryo-Spintornics

Blügel, S.FZJ*

2025

Abstract: With the advent of quantum technology and quantum computing, devices at cryogenic temperature become much more wide spread. This also opens opportunities to include superconducting interfaces into the scientific game. For example, the combination of superconductors with magnetic or topological materials offers a playground where new phenomena such as topological superconductivity, Majorana zero modes or superconducting spintronics can emerge. Sofar, superconductivity was mostly investigated on the basis of singles-band models. We changed this providing a materials specific description of complex superconducting heterostructures based on density functional theory by developing the Kohn­ Sham Bogoliubov-de Gennes (KS-BdG) method [1] into the Julich Korringa-Kohn-Rostoker Greenfunction method UuKKR) [2]. By this we turn from a single band model to multiband effects in hybrid structures, which provides a new rich playground for unconventional superconductivity. I briefly present our method and will show several examples. One example is the Au/Al heterostructure [3], which allows us to predict finite-energy superconducting pairing due to the interplay of the Rashba surface state of Au, with the hybridization to the electronic structure of superconducting Al. We investigate the nature of the induced superconducting pairing, and we quantify its mixed singlet-triplet character. Our findings demonstrate general recipes to explore real material systems that exhibit interorbital pairing away from the Fermi energy.AcknowledgementsThe work was carried out with Philipp Rur3,mann and Bjorn Trautzettel. Work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy-Cluster of Excellence Matter and Light for Quantum Computing (ML4Q) EXC 2004/1-390534769 and through SFB-1238 (project C1) as well as ERC grant 856538 (project "3D MAGIC").References[1] P. Rüßmann and S. Blugel, Phys. Rev. B 105, 125143 (2022).[2] P. Rüßmann, et al, JuDFTteam/aiida-spirit (2023 [10.5281/ZENODO. 8070769][3] P. Rüßmann et al., Phys. Rev. Research 5, 043181 (2023).

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Contributing Institute(s):

1. Quanten-Theorie der Materialien (PGI-1)

Research Program(s):

1. 5211 - Topological Matter (POF4-521) (POF4-521)
2. DFG project G:(GEPRIS)390534769 - EXC 2004: Materie und Licht für Quanteninformation (ML4Q) (390534769) (390534769)
3. SFB 1238 C01 - Strukturinversionsasymmetrische Materie und Spin-Orbit-Phänomene mittels ab initio (C01) (319898210) (319898210)
4. 3D MAGiC - Three-dimensional magnetization textures: Discovery and control on the nanoscale (856538) (856538)

Appears in the scientific report 2025

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