Presentation Information

[25p-71B-13]Topological Dirac semimetal α-Sn / superconducting β-Sn in-plane heterostructures by laser lithography

〇Takahiro Saeki1, Keita Ishihara1, Le Duc Anh1,2,3, Masaaki Tanaka1,3 (1.Tokyo Univ., 2.PRESTO JST, 3.CSRN)


Topological superconductor,Nanowire,Josephson junction

We explore a new method to fabricate superconducting β-Sn/topological Dirac semimetal α-Sn planar junctions using a laser beam. Single-crystalline α-Sn thin films (thickness of 40 nm) are grown on InSb (001) substrates using molecular beam epitaxy (MBE). The α-Sn film is then partially transformed to β-Sn by laser irradiation using a laser writer. We successfully fabricate β-Sn nanoscale structures such as a nanowire with width 750 nm and a planar Josephson junction with two β-Sn electrodes separated by an α-Sn area of 200 nm. The irradiated Sn (β-Sn) exhibits superconductivity below 4 K. By characterizing microscopic structures of the β-Sn/α-Sn using transmission electron microscopy and atomic force microscopy, we confirm good β-Sn/α-Sn interfaces, which are much improved from those fabricated previously using focused ion beam. This demonstration opens a new way to fabricate planar superconductor/topological material nanostructures and devices based on elemental Sn platform.