10.26165/JUELICH-DATA/XJICAR Jalil, Abdur Rehman(PGI-9 and JARA-FIT)Schmitt, Tobias, W.(PGI-9 and JARA-FIT)Rüßmann, Philipp(PGI-1 and University of Würzburg)Wei, Xian-Kui(ER-C)Frohn, Benedikt(PGI-9 and JARA-FIT)Schleenvoigt, Michael(PGI-9 and JARA-FIT)Wittl, Wilhelm(PGI-9)Hou, Xiao(JARA-FIT and GFE, RWTH)Schmidt, Anne(PGI-9 and JARA-FIT)Underwood, Kaycee(PGI-9)Bihlmayer, Gustav(PGI-1)Luysberg, Martina(ER-C)Mayer, Joachim(ER-C and GFE, RWTH)Blügel, Stefan(PGI-1)Grützmacher, Detlev(PGI-9 and JARA-FIT)Schüffelgen, Peter(PGI-9 and JARA-FIT) Jülich DATA 2024 Proximity-induced superconductivity in hybrid devices of topological insulators and superconductors offers a promising platform for the pursuit of elusive topological superconductivity and its anticipated applications, such as fault-tolerant quantum computing. To study and harness such hybrid devices, a key challenge is the realization of highly functional material interfaces with a suitable superconductor featuring 2e-periodic parity-conserving transport to ensure a superconducting hard-gap free of unpaired electrons, which is important for Majorana physics. A superconductor well-known for this characteristic is Al, however, its direct integration into devices based on tetradymite topological insulators has so far been found to yield non-transparent interfaces. By focusing on Bi₂Te₃-Al heterostructures, this study identifies detrimental interdiffusion processes at the interface through atomically resolved structural and chemical analysis, and showcase their mitigation by leveraging different interlayers – namely Nb, Ti, Pd, and Pt – between Bi₂Te₃ and Al. Through structural transformation of the interlayer materials (X) into their respective tellurides (XTe₂) atomically-sharp epitaxial interfaces are engineered and further characterized in low-temperature transport experiments on Al-X-Bi₂Te₃-X-Al Josephson junctions and in complementary density functional theory calculations. By demonstrating functional interfaces between Bi₂Te₃ and Al, this work provides key insights and paves the way for the next generation of sophisticated topological devices. Rüßmann, Philipp(PGI-1 / IAS-1)