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

Angle-resolved photoemission spectroscopy is used to track the evolution of the electronic band structure of TaSe3 across a strain-driven topological phase transition. 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 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 and spin- and angle-resolved photoemission spectroscopy to visualize the strain-driven band-structure evolution of the quasi-one-dimensional superconductor TaSe3. We demonstrate that it undergoes reversible strain-induced topological phase transitions from a strong topological insulator phase with spin-polarized, quasi-one-dimensional topological surface states, to topologically trivial semimetal and band insulating phases. The quasi-one-dimensional superconductor TaSe3 provides a suitable platform for engineering the topological spintronics, for example as an on/off switch for a spin current that is robust against impurity scattering.

Automated summary

Angle-resolved photoemission spectroscopy is utilized to track the evolution of the electronic band structure of TaSe3 during a strain-driven topological phase transition. It is demonstrated that the quasi-one-dimensional superconductor TaSe3 undergoes reversible strain-induced topological phase transitions from a strong topological insulator phase to topologically trivial semimetal and band insulating phases. TaSe3 provides a promising platform for engineering topological spintronics, such as an on/off switch for a spin current resistant to impurity scattering.