Finite-length effects and Coulomb interaction in Josephson junctions based on Ge quantum wells and probed with microwave spectroscopy

S.C. ten Kate; D.C. Ohnmacht; M. Coraiola; T. Antonelli; S. Paredes; F.J. Schupp; M. Hinderling; S.W. Bedell; W. Belzig; J.C. Cuevas; A.E. Svetogorov; F. Nichele; D. Sabonis

doi:10.1103/hb1h-8jn9

Finite-length effects and Coulomb interaction in Josephson junctions based on Ge quantum wells and probed with microwave spectroscopy

S.C. ten Kate, D.C. Ohnmacht, M. Coraiola, T. Antonelli, S. Paredes, F.J. Schupp, M. Hinderling, S.W. Bedell, W. Belzig, J.C. Cuevas, A.E. Svetogorov, F. Nichele, D. Sabonis

DOI 10.1103/hb1h-8jn9 · Physical Review Applied

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Abstract

Proximitized Ge quantum wells have emerged as a platform for studying Andreev bound states (ABSs) due to their expected strong spin-orbit interaction and high mobility. Here, we used microwave spectroscopy techniques to investigate ABSs in Josephson junctions (JJs) realized in proximitized Ge quantum wells. Spectroscopic signatures observed in a 350-nm junction indicated the presence of multiple ABSs and were reproduced with a model including finite-length effects. The ABS spectra measured for a 1.2-μm junction were explained by a model including three ABSs in two conduction channels and finite Coulomb interaction. Our work highlights the importance of interactions in JJs and serves as a basis for understanding and manipulating ABSs in Ge-based hybrid devices.

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