Topological Phase Transition in Sb₂Mg₃ Assisted by Strain

Topological insulating materials with dissipationless surface states promise potential applications in spintronic materials. Through density functional theory, we proposed a new class of topological phase transition in Sb2Mg3 on the basis of tensile strain. At the equilibrium state, Sb2Mg3 corresponds to a normal insulator, and under the influence of tensile strain, the band gaps are gradually tuned. At ε = 7.2%, the nontrivial phase is achieved due to spin–orbital coupling (SOC), and a nontrivial topological phase band gap of 0.22 eV is opened. As a result, the Dirac cone is locked in the bulk, which is associated to px,y band crossing. Interestingly, the tuning of nontrivial topological properties with tensile strain leading to spin saturation indicates an orbital-filtering effect. The surface state of the Sb2Mg3 material is determined by the topological invariant, Z2 = 1, at the critical tensile strain in the presence of the SOC effect. This study enhances the scope of topological insulators and current platforms to design new spintronic devices