講演情報
[17p-K102-11]Superconductivity of In-doped α-Sn thin films grown by molecular beam epitaxy
〇Keidai Toyoshima1, Hideki Maki1, Le Duc Anh1,2, Masaaki Tanaka1,2 (1.Univ. of Tokyo, 2.CSRN, Univ. of Tokyo)
キーワード：
topological Dirac semimetal、superconductivity、alpha-Sn
Our group reported that α-Sn grown on an InSb substrate exhibited superconductivity 20 months after growth, probably originating from the doping effect when indium (In) atoms are diffused from the InSb buffer layer into the overgrown α-Sn thin film.
In this work, we grew 30nm-thick In-doped α-Sn films with In concentrations of 0.6, 1.8, 3, 5, 8.5 and 12.5% on InSb (001) substrates by molecular beam epitaxy. Zero resistance was observed in the samples with In-doping concentrations of more than 5% In, where the superconducting transition temperature (TC) increased with increasing the In concentration. We measured the critical magnetic field HC and critical current IC under various magnetic field directions. In-plane angular dependences of HC and IC were found to show sharp peaks when the magnetic field and the current are parallel. In addition, HC was maximized when the magnetic field is perpendicular to the current. These angular dependences of superconducting properties are unique to In-doped Sn and suggest a contribution of TDS α-Sn to the superconductivity.
In this work, we grew 30nm-thick In-doped α-Sn films with In concentrations of 0.6, 1.8, 3, 5, 8.5 and 12.5% on InSb (001) substrates by molecular beam epitaxy. Zero resistance was observed in the samples with In-doping concentrations of more than 5% In, where the superconducting transition temperature (TC) increased with increasing the In concentration. We measured the critical magnetic field HC and critical current IC under various magnetic field directions. In-plane angular dependences of HC and IC were found to show sharp peaks when the magnetic field and the current are parallel. In addition, HC was maximized when the magnetic field is perpendicular to the current. These angular dependences of superconducting properties are unique to In-doped Sn and suggest a contribution of TDS α-Sn to the superconductivity.