Results

Publications

SC-1 etching of Nb and TiN thin films

A. Gutiérrez-Cruz, K. A. C. Rathnathilaka, J. M. Taskinen, T. Vaimala, K. Grigoras, H. Mishra, R. Upadhyay, J. Senior, and A. Ronzani.

arXiv preprint: https://doi.org/10.48550/arXiv.2605.28343

Dry etching techniques, ubiquitous in microelectronics fabrication, often result in challenging levels of undesired collateral plasma-induced damage. In this work, we demonstrate a wet etching alternative for the patterning of niobium (Nb) and titanium nitride (TiN) thin films … Read more

Spontaneous supercurrents and vortex depinning in two-dimensional arrays of 𝜑₀ Josephson junctions

S. Reinhardt, A. Penner, J. Berger, C. Baumgartner, S. Gronin, G. Gardner, T. Lindemann, M. Manfra, L. Glazman, F. von Oppen, N. Paradiso, & C. Strunk

Physical Review B 112.22, 224503 (2025) https://doi.org/10.1103/31zv-84hw

Two-dimensional arrays of ballistic Josephson junctions are important as model systems for synthetic quantum materials. Here, we investigate arrays of multiterminal junctions which exhibit a phase difference … Read more

Superconducting junctions with flat bands

P. Virtanen, R. P. S. Penttilä, P. Törmä, A. Díez-Carlón, D. K. Efetov, & T. T. Heikkilä

Physical Review B 112, L100502 (2025) https://doi.org/10.1103/7f1y-kjyl

We analyze the properties of flat-band superconductor junctions that behave differently from ordinary junctions containing only metals with Fermi surfaces. In particular, we show how in the tunneling limit the critical Josephson current between flat-band superconductors … Read more

Magnetoelectric effects in diffusive two-dimensional superconductors studied by the nonlinear 𝜎 model

P. Virtanen

Physical Review B 111.2, 024510 (2025) https://doi.org/10.1103/PhysRevB.111.024510

We describe a numerical approach to modeling magnetoelectric effects generated by spin-orbit coupling in inhomogeneous diffusive two-dimensional (2D) superconductors. It is based on direct … Read more

Superconducting diode effect in diffusive superconductors and Josephson junctions with Rashba spin-orbit coupling

S. Ilić, P. Virtanen, D. Crawford, T. T. Heikkilä, & F. S. Bergeret

Physical Review B 110, L140501 (2024) https://doi.org/10.1103/PhysRevB.110.L140501

We characterize the superconducting diode effect (SDE) in two-dimensional diffusive structures with Rashba spin-orbit coupling using the quasiclassical formalism. We consider both homogeneous superconductors … Read more

Wafer-scale CMOS-compatible graphene Josephson field-effect transistors

A. A. Generalov, K. L. Viisanen, J. Senior, B. R. Ferreira, J. Ma, M. Möttönen, M. Prunnila, & H. Bohuslavskyi

Applied Physics Letters 125, 012602 (2024) https://doi.org/10.1063/5.0203515

Electrostatically tunable Josephson field-effect transistors (JoFETs) are one of the most desired building blocks of quantum electronics. Applications of JoFETs range from parametric amplifiers and superconducting qubits to a variety of integrated superconducting circuits… Read more

Link between supercurrent diode and anomalous Josephson effect revealed by gate-controlled interferometry

S. Reinhardt, T. Ascherl, A. Costa, J. Berger, S. Gronin, G. C. Gardner, T. Lindemann, M. J. Manfra, J. Fabian, D. Kochan, C. Strunk, & N. Paradiso

Nature communications 15, 4413 (2024) https://doi.org/10.1038/s41467-024-48741-z

In Josephson diodes the asymmetry between positive and negative current branch of the current-phase relation leads to a polarity-dependent critical current and Josephson inductance … Read more

Nonreciprocal Josephson Linear Response

P. Virtanen, & T. T. Heikkilä

Physical Review Letters 132, 046002 (2024) https://doi.org/10.1103/PhysRevLett.132.046002

We consider the finite-frequency response of multiterminal Josephson junctions and show how nonreciprocity in them can show up at linear response, in contrast to the static Josephson diodes featuring nonlinear nonreciprocity. At finite frequencies, the response contains dynamic contributions to the Josephson admittance … Read more

Datasets and Repositories

Open code repository for simulating hybrid diffusive weak links, JoFETs, and superconducting diodes

JYU Condensed Matter Theory, University of Jyväskylä

gitlab.jyu.fi/jyucmt

Data archive of “Link between supercurrent diode and anomalous Josephson effect revealed by gate-controlled interferometry