講演情報
[20p-C501-7]Superconductivity in an α-Sn thin film
〇Tomoki Hotta1, Anh Le Duc1,2, Masaaki Tanaka1,3 (1.EEIS, Univ. Tokyo, 2.PRESTO, JST, 3.CSRN, Univ. Tokyo)
キーワード：
topological Dirac semimetal、superconductivity、quantum oscillation
We have found that superconductivity occurs in a high-quality α-Sn thin film by the band structure alternation. We have grown a 5-nm-thick α-Sn thin film on an N-type InSb (001) substrate by molecular beam epitaxy (MBE). When measured 6 months after the growth, the sample shows semiconducting temperature dependence of resistance and clear Shubnikov-de Haas (SdH) oscillations with a single band. Surprisingly, the same sample shows a superconductivity when measured 20 months after the growth with the critical temperature (Tc) of 4.2 K. Temperature dependence of critical magnetic field (Hc) are well fitted by the standard Ginzburg-Landau theory with ξGL = 20.5 nm. This superconducting α-Sn shows clear SdH oscillations with two bands, F and Fnew. The coherence length ξ of Fnew is 19.71 nm. Because ξ is close to ξGL, superconductivity may originate from Fnew. This new superconducting band in α-Sn may be formed by interdiffusion of In atoms from the InSb buffer layer. Our high quality superconducting α-Sn is a promising material for the application to superconducting quantum computers.