A peer-reviewed experiment joined thin niobium diselenide layers with a one-degree twist and measured different current limits in opposite directions. The asymmetry reached 27.6 per cent in a small magnetic field. Thicker devices showed a weaker response. Separate quantum-circuit simulations examined how this directional effect changes energy levels, with the results depending on the model’s parameters.
Researchers joined two niobium diselenide layers with a one-degree twist and measured how much current each direction could carry before resistance appeared. The peer-reviewed Nature Communications study reports a superconducting diode effect: the limits differ when the current is reversed. The thinnest device, with a total thickness of sixteen nanometres, became superconducting below 6.87 kelvin.[1]
In that device, the asymmetry reached 27.6 per cent at a perpendicular magnetic field of minus thirteen oersted. The percentage compares the two critical-current magnitudes; it does not measure conversion of energy into useful output. Thirty- and sixty-nanometre devices showed weaker directional asymmetry. Rotating an in-plane field also changed the response, giving the researchers a way to examine how field direction affects transport.[1]
The authors tested sample alignment to distinguish an in-plane response from an accidentally perpendicular field. They also cautioned that several oersted of residual field from trapped magnetic flux could not be completely excluded when the applied field was nominally zero.[1]
A separate QuTiP simulation used the measured asymmetry to model quantum circuits. At a selected ratio of Josephson to charging energy, a asymmetry of 27.6 per cent left two bound energy levels in the model’s central potential well; smaller or larger values changed that count. The authors simulated directional quantum-state transfer, rather than demonstrating an operating qubit made from these devices. They identify fabrication and testing in practical quantum circuits as further experimental work.[1]
