Scanning tunneling microscopic observation of enhanced superconductivity in epitaxial Sn islands grown on SrTiO3 substrate

作     者：Zhibin Shao Zongyuan Zhang Hui Yuan Haigen Sun Yan Cao Xin Zhang Shaojian Li Habakubaho Gedeon Tao Xiang Qi-Kun Xue Minghu Pan 

作者机构：School of PhysicsHuazhong University of Science and TechnologyWuhan 430074China Institute of PhysicsChinese Academy of ScienceBeifing 100190China Collaborative Innovation Center of Quantum MatterBeijing 100084China State Key Laboratory of Low-Dimensional Quantum PhysicsTsinghua UniversityBejiing 100084China 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2018年第63卷第20期

页      面：1332-1337页

核心收录：

学科分类：07[理学] 08[工学] 

基　　金：the financial support by the National Natural Science Foundation of China(11574095 and 11604106) 

主　　题：Sn islands/SrTiO3 Interface-enhanced superconductivity Molecular beam epitaxy Scanning tunneling microscope Scanning tunneling spectroscopy 

摘      要：Recent experimental and theoretical studies of single-layer FeSe film grown on SrTiO_3 have revealed interface enhanced superconductivity, which opens up a pathway to promote the superconducting transition temperature. Here, to investigate the role of SrTiO_3 substrate in epitaxial superconducting film, we grew a conventional superconductor b-Sn(bulk T_c～ 3.72 K) onto SrTiO_3 substrate by molecular beam epitaxy. By employing scanning tunneling microscope and spectroscopic measurements, an enhanced Tcof 8.2 K is found for epitaxial b-Sn islands, deduced by fitting the temperature dependence of the gap values using the BCS formula. The observed interfacial charge injection and enhanced electron–phonon coupling are responsible for this Tcenhancement. Moreover, the critical field of 8.3 T exhibits a tremendous increase due to the suppression of the vortex formation. Therefore, the coexistence of enhanced superconductivity and high critical field of Sn islands demonstrates a feasible and effective route to improve the superconductivity by growing the islands of conventional superconductors on perovskite-type titanium oxide substrates.