Controlling strong correlations of high temperature superconductors with Van der Waals heterostructures

• Applicant: Privatdozent Nicola Poccia, Ph.D.
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452128813

Recent progress in integrating thin Bi-2212 van der Waals crystals into nanodevices has spurred theoretical predictions for coherent superposition of d-wave orders. Challenges in stacking Bi-2212 have been addressed in the first funding phase, leading to the observation of spontaneously time broken states in optimally doped twisted bilayers Bi-2212 heterostructures. In addition, in the first funding phase, silicon nitride microprinted circuits boards have been created with the scope to integrate atomically thin cuprates crystals in more complex electrical circuits. In the second funding phase, we expect that the innovative methods for electrical circuit realization can facilitate the exploration of quantum states across cuprate interfaces with varying oxygen interstitials doping gradients. The work program includes specifically three main tasks: testing silicon nitride microprinted circuits with a 0° angle cuprate Josephson junction, realizing underdoped-optimally doped cuprate Josephson junctions, and determining the electronic transport role of doping gradients across the interface in twisted cuprate Josephson junctions. Methodologically, cryogenic stacking in an inert atmosphere is used to fabricate twisted cuprate interfaces, while silicon nitride microprinted circuits offer advantages in creating via contacts with minimal damage and high resolution. The project involves low-temperature measurements to analyze the I-V characteristics of the fabricated heterostructures, providing insights into their electronic properties as a function of temperature and magnetic fields.

• DFG Programme: Research Grants
• International Connection: Italy
• Cooperation Partners: Privatdozent Dr. Domenico Montemurro; Professor Dr. Francesco Tafuri