Phys. Rev. Applied 25, 044028 (2026)
Proximity coupling of bilayer graphene (BLG) to transition metal dichalcogenides (TMDs) offers a promising route to engineer gate-tunable spin-orbit coupling (SOC) while preserving BLG’s exceptional electronic properties. This tunability arises from the layer-asymmetric electronic structure of gapped BLG, where SOC acts predominantly on the layer in contact with the TMD. Here, we present a high-quality BLG/⁢WSe₂ device with a proximity-induced SOC gap and excellent electrostatic control. Operating in a quasiballistic regime, our double-gated heterostructure allows a gate-defined p-n-p cavity to be formed and clear weak antilocalization (WAL) features to be shown consistent with Rashba-type SOC. At lower hole densities, a transition to a pronounced weak-localization (WL) feature is observed, signaling transport through a single spin-split valence band. These findings – in agreement with calculations – provide direct spectroscopic evidence of a proximity-induced spin-split band in BLG and underscore the potential of BLG/TMD heterostructures for spintronics and spin-based quantum technologies.

Roxana Anghel won one of the three poster prizes at the IWEPNM Winterschool in Kirchberg with her poster on "Asymmetric electron-hole double quantum dots in bilayer graphene". Congratulations!

Nano Letters 26, 2119 (2026)
We report low-temperature measurements of two adjacent, gate-defined Josephson junctions (JJs) in magic-angle twisted bilayer graphene (MATBG) at a moiré filling factor near ν = -2. We show that both junctions exhibit a prominent, gate-tunable Josephson diode effect, which we explain by a combination of large kinetic inductance and non-uniform supercurrent distribution. Despite their proximity, the JJs display differences in their interference patterns and different diode behavior, underscoring that microscopic inhomogeneities such as twist angle variations shape the non-uniform supercurrent and drive the diode behavior. As a result, the nonreciprocal supercurrent can be tuned by gate voltage, enabling tuning of the diode efficiency and even reversing the polarity at fixed magnetic fields. Our findings offer potential routes for tailoring Josephson diode performance in superconducting quantum circuits.