Strain-controlled evolution of electronic structure indicating topological phase transition in the quasi-one-dimensional superconductor TaSe3

Abstract

We report the signature of a strain-controlled topological phase transition in the electronic structure of a quasione-dimensional superconductor TaSe3. Using angle-resolved photoemission spectroscopy and first-principles calculation, TaSe3 is identified to be in a weak topological insulator phase which has topologically nontrivial surface states only at the allowed planes. Under uniaxial tensile strain, a Dirac point and the topological surface state emerge on the originally forbidden (10 (1) over bar) plane, which demonstrates the transition to a strong topological insulator phase. Our results accomplish the experimental realization of possible topological insulating phases in TaSe3 and highlight the possibility of coupling the superconductivity with two distinct topological insulating phases in a controllable manner.