Two-dimensional superconductivity at the interface of a Bi2Te3/FeTe heterostructure

• Published in: Nature communications 2014-06, Vol.5 (1), p.4247-4247, Article 4247
• Main Authors: He, Qing Lin, Liu, Hongchao, He, Mingquan, Lai, Ying Hoi, He, Hongtao, Wang, Gan, Law, Kam Tuen, Lortz, Rolf, Wang, Jiannong, Sou, Iam Keong
• Format: Article
• Language: English
• Subjects: 639/301/119/544; 639/766/119/1003; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms5247

The realization of superconductivity at the interface between a topological insulator and an iron-chalcogenide compound is highly attractive for exploring several recent theoretical predictions involving these two new classes of materials. Here we report transport measurements on a Bi 2 Te 3 /FeTe heterostructure fabricated via van der Waals epitaxy, which demonstrate superconductivity at the interface, which is induced by the Bi 2 Te 3 epilayer with thickness even down to one quintuple layer, though there is no clear-cut evidence that the observed superconductivity is induced by the topological surface states. The two-dimensional nature of the observed superconductivity with the highest transition temperature around 12 K was verified by the existence of a Berezinsky–Kosterlitz–Thouless transition and the diverging ratio of in-plane to out-plane upper critical field on approaching the superconducting transition temperature. With the combination of interface superconductivity and Dirac surface states of Bi 2 Te 3 , the heterostructure studied in this work provides a novel platform for realizing Majorana fermions. Under normal conditions neither FeTe nor Bi 2 Te 3 are superconductors, the former being a semiconductor and the latter a topological insulator. However, He et al . show that when a Bi 2 Te 3 layer, even down to one-quintuple-layer in thickness, is grown on FeTe, superconductivity develops at the interface.