The Coexistence of Superconductivity and Topological Order in the Bi2Se3 Thin Films

• Published in: Science (American Association for the Advancement of Science) Vol. 336; no. 6077; pp. 52 - 55
• Main Authors: WANG, Mei-Xiao, CANHUA LIU, XU, Zhu-An, YING LIU, ZHANG, Shou-Cheng, DONG QIAN, JIA, Jin-Feng, XUE, Qi-Kun, XU, Jin-Peng, FANG YANG, LIN MIAO, YAO, Meng-Yu, GAO, C. L, CHENYI SHEN, XUCUN MA, CHEN, X
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 06.04.2012; The American Association for the Advancement of Science
• Subjects: Broken symmetry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Devices; Exact sciences and technology; Observation; Physics; Spectroscopy; Superconducting materials (excluding high-tc compounds); Superconductivity; Superconductors; Symmetry; Thin films; Three dimensional; Topological manifolds; Topology; Fermions; Superconducting energy gap; Superconductivity; Angle resolved photoemission spectroscopy; Momentum; Coexistence; Symmetry breaking; Thin films; Thickness; Bismuth selenides; Scanning tunneling microscopy; Topological insulator; Superconductors; Heterostructures; Time reversal
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1216466

Three-dimensional topological insulators (TIs) are characterized by their nontrivial surface states, in which electrons have their spin locked at a right angle to their momentum under the protection of time-reversal symmetry. The topologically ordered phase in TIs does not break any symmetry. The interplay between topological order and symmetry breaking, such as that observed in superconductivity, can lead to new quantum phenomena and devices. We fabricated a superconducting TI/superconductor heterostructure by growing dibismuth triselenide (Bi(2)Se(3)) thin films on superconductor niobium diselenide substrate. Using scanning tunneling microscopy and angle-resolved photoemission spectroscopy, we observed the superconducting gap at the Bi(2)Se(3) surface in the regime of Bi(2)Se(3) film thickness where topological surface states form. This observation lays the groundwork for experimentally realizing Majorana fermions in condensed matter physics.