Observation of Topological Electronic Structure in Quasi-1D Superconductor TaSe3

Topological superconductors (TSCs), with the capability to host Majorana bound states that can lead to non-Abelian statistics and application in quantum computation, have been one of the most intensively studied topics in condensed matter physics recently. To date, only a few compounds have been proposed as candidates of intrinsic TSCs, such as doped topological insulator CuxBi2Se3 and iron-based superconductor FeTe0.55Se0.45. Here, by carrying out synchrotron- and laser-based angle-resolved photoemission spectroscopy, we systematically investigated the electronic structure of a quasi-one-dimensional superconductor TaSe3 and identified the non-trivial topological surface states. In addition, our scanning tunneling microscopy study revealed a clean cleaved surface with a persistent superconducting gap, proving it suitable for further investigation of potential Majorana modes. These results prove TaSe3 as a stoichiometric TSC candidate that is stable and exfoliable and therefore a promising platform for the study of rich novel phenomena and application potentials. [Display omitted] •Persistent superconductivity gap was observed on the clean cleaved surface•Topological nature was confirmed by observation of topological surface states•A suitable research platform on topological superconductivity was introduced A topological superconductor (TSC) is a new type of superconductor with non-trivial topology in its bulk electronic structure, which has great potential in both fundamental research and application. However, despite the intensive research efforts worldwide, to date only a few intrinsic (non-heterostructures) materials have been proposed as TSC candidates. In this work, following the theoretical prediction, we experimentally studied a newly proposed TSC candidate, TaSe3. The topological non-trivial surface states were directly observed by using angle-resolved photoemission spectroscopy, while the superconductivity of the compound was examined by both transport and scanning tunneling microscopy measurement. Therefore, TaSe3 was proved to be a promising candidate as a TSC, and a promising research platform for the related novel physics phenomena. Only a few intrinsic materials have been found to be candidates as a topological superconductor, which has promising research and application potentials. In this work, following the theoretical prediction, we experimentally proved TaSe3 to be a new candidate by proving both the superconductivity and topological nat