Work

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

Year: 2025

Type: article

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 - μ m 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.

Source: Physical Review Applied

DOI: 10.1103/hb1h-8jn9