WELCOME TO MY RESEARCHER PAGE

I am an experimental physicist working on nonreciprocal superconductivity in the Moodera lab at MIT. I performed my PhD in the University of Groningen under the supervision of prof. Bart van Wees where I worked on spin transport in graphene. Next, I moved to the nanodevices group at CIC nanoGUNE in San Sebastian, where I worked on spin transport and spin-to-charge conversion in van der Waals heterostructures made with different layered materials including MoS2, WSe2 and NbSe2 among others. From June 2021 until August 2023 I was a Marie Curie Fellow at TU Delft working on quantum transport in bilayer graphene-based quantum dots and quantum point contacts where I explored the physics of electrostatically-defined quantum point contacts in bilayer graphene among other mesoscopic physics experiments. I am currently a postdoctoral researcher at the Plasma Science and Fusion Center at MIT, working on superconducting diode effects.

Research projects

Spin transport in graphene

To understand what happens to the electron spins in graphene, we used ferromagnets to make contacts to graphene and, by passing a current through these contacts, we transferred the spins from the ferromagnet to the graphene channel and detect them so that we could measure their dynamics.

Here, we used a drift current to accelerate and slow down the spins, which allowed us to enhance the distance traveled by the spins before relaxing, and thus, the measured spin signal.

JI-A et al. Nano Letters (2016)

Spin Hall effect in graphene/MoS2

To make graphene more useful for spin transport, we placed it in contact with MoS2. We found that it converts spin currents into charge currents, so we only needed one Ferromagnetic contact to measure spin signals.

C. K. Safeer, JI-A et al. Nano Letters (2019)

Spin-orbit proximity in graphene/WSe2

We connected it with WSe2, a semiconductor with very high spin-orbit coupling. We found that it transferred so much spin-orbit coupling to the graphene that the spins in graphene were reversed without applying any magnetic fields.

JI-A et al. Physical Review Letters (2021)

Conversion of spins pointing in all possible directions into charge currents

The ability of a material to convert spins into measurable voltages is typically limited by the symmetry of the underlying material system. The symmetry of graphene/NbSe2 van der Waals heterostructures depends on the stacking angle between the layers and results in the conversion of spins pointing toward all physical directions into measurable voltages.

JI-A et al. 2D Materials (2022)

Ballistic transport between quantum point contacts in bilayer graphene

The behavior of electrons in solid-state systems depends on the material's properties, such as the shape of its Fermi surface. Bilayer graphene is a semiconductor with a triangularly distorted Fermi surface that is expected to influence ballistic transport. Observing its effects requires very clean devices where the edges are defined electrostatically, allowing for specular reflection of electrons at these edges. In addition, the electrostatically defined contacts in these samples emit valley-polarized current jets, which we used to create a source of valley-polarized currents.

JI-A et al. Nano Letters (2023), Physical Review Letters (2024)

Superconducting rectifiers for cryogenic AC-DC conversion

Superconducting diodes can carry a different amount of current in opposite directions while remaining superconducting. This makes the conversion of AC currents into DC at cryogenic temperatures possible, which would have a huge impact for superconducting quantum and classical computing. We realized the first superconducting rectifiers capable of converting AC currents into DC below the liquid He temperature.

JI-A et al. arXiv (2024), see also Castellani et al arXiv (2024)