Strain-induced topological phase transition in phosphorene and phosphorene nanoribbons

TL;DR

This paper predicts a topological phase transition in phosphorene induced by axial strain, revealing potential for strain-engineered topological properties and robust edge states in nanoribbons.

Contribution

It derives a low-energy tight-binding Hamiltonian including spin-orbit interaction and demonstrates strain-induced topological phase transitions in phosphorene and nanoribbons.

Findings

Strain induces a topological phase transition in phosphorene.

Protected edge states form in topological nanoribbons.

Energy gaps remain large at room temperature.

Abstract

Using the tight-binding (TB) approximation with inclusion of the spin-orbit interaction, we predict a topological phase transition in the electronic band structure of phosphorene in the presence of axial strains. We derive a low-energy TB Hamiltonian that includes the spin-orbit interaction for bulk phosphorene. Applying a compressive biaxial in-plane strain and perpendicular tensile strain in ranges where the structure is still stable leads to a topological phase transition. We also examine the influence of strain on zigzag phosphorene nanoribbons (zPNRs) and the formation of the corresponding protected edge states when the system is in the topological phase. For zPNRs up to a width of 100 nm the energy gap is at least three orders of magnitude larger than the thermal energy at room temperature.