Dry dilution refrigerator with vector magnet

• Subject Area: Condensed Matter Physics
• Term: Funded in 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 464847925

We apply for a dry 3He/4He-dilution refrigerator with a cooling power of 250 microwatt at 100 mK, a base temperature of 10 mK, and equipped with a superconducting vector magnet allowing for magnetic fields of 1/3/6 Tesla in the x/y/z-directions.The instrument will be used to gain a deeper understanding of spin-orbit interaction effects in super¬conductivity both in epitaxial Al/InAs-based nanopatterned arrays of Josephson junc-tions and in extended quasi-two-dimensional films. We will investigate novel magneto-electric effects, chiral, and topological phases with the prospect of applications in quantum electronic circuits. Besides standard transport experiments, our experimental tool will be the newly implemented technique of kinetic inductance measurements, which will be systematically applied in two research directions:1) Investigation of spin-orbit interaction-induced supercurrent response, spontaneous supercurrents, and the corresponding magnetization patterns in devices based on epitaxial Al/InAs heterostructures: Here we will combine the above techniques mentioned in order to uncover the expected unconventional flow patterns in combined perpendicular and in-plane magnetic fields. The perpendicular field component tunes the frustration in the system, the in-plane field affects together with the spin-orbit interaction the spin-texture of the Andreev bound states. We expect states with exotic magnetic order resulting from the interaction between the spontaneous ring currents that emerge from spin-orbit interaction in absence of time-reversal symmetry and that can be tuned with the strength and direction of the in-plane magnetic field.2) Search for unconventional superconductivity and magnetoelectric effects in two-dimensional exotic superconductors with strong spin-orbit interaction: We want to employ inductance measurements in order to investigate magneto-electric anisotropy and possible unconventional pairing in Al/InAs(110) and several particularly interesting compound metals: 1) few-layer NbSe2, 2) thin super¬conducting Bi/Ni-bilayers, 3) epitaxial Au/V-bilayers. Common to all material systems is the combinations of supercon-ductivity with extremely strong spin-orbit interaction, and the corresponding prospects for unconventional and topological superconductivity.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Trockener Mischkryostat mit Vektormagnet
• Instrumentation Group: 8550 Spezielle Kryostaten (für tiefste Temperaturen)
• Applicant Institution: Universität Regensburg
• Leader: Professor Dr. Christoph Strunk