Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 18: Superconductivity: Poster
TT 18.2: Poster
Monday, March 18, 2024, 15:00–18:00, Poster C
Nanoscale Characterization of Superconducting Nitrides for Qubits — •Janine Lorenz1,2,3, Amin Karimi1, Yorgo Haddad4, Sven Linzen5, Rami Barends4, F. Stefan Tautz1,2,3, and Felix Lüpke1,2 — 1Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, Germany — 2Jülich Aachen Research Alliance (JARA) - Fundamentals of Future Information Technology, Germany — 3Institut für Experimentalphysik IV A, RWTH Aachen, Germany — 4Peter Grünberg Institut (PGI-13), Forschungszentrum Jülich, Germany — 5Leibniz Institute of Photonic Technology, Friedrich-Schiller-Universität Jena, Germany
Superconducting nitrides like NbTiN are promising candidates for advancing the performance of transmon qubits as they offer distinct advantages compared to conventional aluminum-based quantum circuits. Notably, NbTiN thin films offer improved chemical stability, show elevated critical temperatures up to 15 K and have a higher kinetic inductance, all of which are important properties for good qubit performance.
Here, we present a comprehensive investigation of superconducting nitride thin films using scanning probe techniques. We find that our polycrystalline 5 nm and 11 nm NbTiN films show a homogeneous superconducting gap throughout the surface. Applying BCS theory we extract critical temperatures of 10 K and 11.5 K, respectively. To improve structural and superconducting properties of our films we explore different post-deposition treatment methods with a focus on thermal annealing in different gas atmospheres.
Keywords: Scanning Tunneling Microscopy; Superconductors; Qubits; NbTiN; NbN