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 

机构地区：[1]School of Physics,Huazhong University of Science and Technology,Wuhan 430074,China [2]Institute of Physics,Chinese Academy of Science,Beifing 100190,China [3]Collaborative Innovation Center of Quantum Matter,Beijing 100084,China [4]State Key Laboratory of Low-Dimensional Quantum Physics,Tsinghua University,Bejiing 100084,China

出　　处：《Science Bulletin》2018年第20期1332-1337,共6页科学通报（英文版）

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

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.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.

关 键 词：SN islands/SrTiO3 Interface-enhanced SUPERCONDUCTIVITY Molecular beam epitaxy SCANNING TUNNELING microscope SCANNING TUNNELING spectroscopy 

分 类 号：N[自然科学总论]