Non-destructive laser nanopatterning of superconducting heterostructures in topological Sn thin films

Heterostructures combining superconductors and topological materials offer promising routes toward topological superconductivity and fault-tolerant quantum computing. A major challenge lies in achieving atomically sharp, coherent interfaces between materials of distinct structural and electronic characteristics. We demonstrate a simple and scalable approach to fabricate planar heterostructures composed of the topological Dirac semimetal α-Sn [1,2] and the superconducting β-Sn phase, realized via focused laser irradiation on α-Sn thin films. The local irradiation triggers a phase transition from α-Sn to β-Sn, yielding atomically smooth interfaces with a root-mean-square surface roughness of only 0.75 nm. The resulting β-Sn exhibits type-I superconductivity with a critical temperature (Tc) of 3.7 K and a Ginzburg–Landau coherence length (ξGL) of 68.2 nm. Moreover, β-Sn nanowires patterned through this laser-induced conversion show a clear superconducting diode effect with a maximum rectification ratio (η) of 10.8%. Our findings establish laser irradiation as a non-destructive and versatile route for realizing high-quality α-Sn/β-Sn heterostructures, paving the way for next-generation superconducting quantum devices.

Ref:

[1] Le Duc Anh, Kengo Takase et al., Adv. Mater. 33, 2104645 (2021)

[2] Le Duc Anh, Keita Ishihara et al., Nature Commun. 15, 8014 (2024)