2D High-Temperature Superconductor Integration in Contact Printed Circuit Boards
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Engineering topics
Montemurro, Domenico
Publications and source records attributed to Montemurro, Domenico.
Twisted cuprate van der Waals heterostructures with controlled Josephson coupling
Twisted van derWaals (vdW) heterostructures offer a unique platform for engineering the efficient Josephson coupling between cuprate thin crystals harboring the nodal superconducting order parameter. Preparing the vdW heterostructures-based Josephson junction comprising stacked cuprates requires maintaining an ordered interface with preserved surface superconductivity. Here, we report the preparation of the Josephson junction out of the stacked Bi 2 Sr 2 CaCu 2 O 8+d crystals using the cryogenic dry transfer technique and encapsulating the junction with an insulating layer, that protects the interface during the electrical contacts evaporation at the 1×10 -6 mbar base pressure. We find that the Josephson critical current $I$ c has a maximum at low twist angles, comparable to that of the bulk intrinsic Josephson junctions, and is reduced by two orders of magnitude at twist angles close to 45°. In conclusion, the reduction of $I$ c occurs due to a mismatch between superconducting $d$-wave order parameters, which suppresses the direct Cooper pair tunneling.
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Encapsulating High–Temperature Superconducting Twisted van der Waals Heterostructures Blocks Detrimental Effects of Disorder
High-temperature cuprate superconductors based van der Waals (vdW) heterostructures hold high technological promise. One of the obstacles hindering their progress is the detrimental effect of disorder on the properties of the vdW-devices-based Josephson junctions (JJs). Here, a new method of fabricating twisted vdW heterostructures made of Bi 2 Sr 2 CuCa 2 O 8+δ , crucially improving the JJ characteristics and pushing them up to those of the intrinsic JJs in bulk samples, is reported. The method combines cryogenic stacking using a solvent-free stencil mask technique and covering the interface by insulating hexagonal boron nitride crystals. Despite the high-vacuum condition down to 10 –6 mbar in the evaporation chamber, the interface appears to be protected from water molecules during the in situ metal deposition only when fully encapsulated. Comparing the current-voltage curves of encapsulated and unencapsulated interfaces, it is revealed that the encapsulated interfaces' characteristics are crucially improved, so that the corresponding JJs demonstrate high critical currents and sharpness of the superconducting transition comparable to those of the intrinsic JJs. Finally, it is shown that the encapsulated heterostructures are more stable over time.
2D materials↗