Visualization of the strain-induced topological phase transition in a quasi-one-dimensional superconductor TaSe3

TL;DR

This study visualizes how applying strain to the quasi-one-dimensional superconductor TaSe3 induces reversible topological phase transitions, enabling potential spintronics applications like on/off spin current switches.

Contribution

It demonstrates strain-driven topological phase transitions in TaSe3 using ARPES, providing a reversible and controllable method for topological state manipulation.

Findings

Reversible topological phase transition observed in TaSe3 under strain

Identification of spin-polarized surface states in the topological phase

Potential application as an on/off spin current switch

Abstract

Control of the phase transition from topological to normal insulators can allow for an on/off switching of spin current. While topological phase transitions have been realized by elemental substitution in semiconducting alloys, such an approach requires the preparation of materials with various compositions, thus it is quite far from a feasible device application, which demands a reversible operation. Here we use angle-resolved photoemission spectroscopy (ARPES) and spin-resolved ARPES to visualize the strain-driven band structure evolution of the quasi-1D superconductor TaSe3. We demonstrate that it undergoes reversible strain-induced topological phase transitions from a strong topological insulator phase with spin-polarized, quasi-1D topological surface states, to topologically trivial semimetal and band insulating phases. The quasi-1D superconductor TaSe3 provides a suitable platform for engineering the topological spintronics, for example as an on/off switch for spin current robust against impurity scattering.