Topological phase transitions on the square-octagon lattice driven by the Rashba spin-orbit coupling and staggered potential

We propose that the topological phase transitions can occur in the square-octagon lattice, when the Rashba spin-orbit coupling and the staggered potential are taken into account. By means of the Fukui-Hatsugai method, topological invariant Z2 is evaluated and the phase diagram is presented as a function of the Rashba spin-orbit coupling and the staggered potential. We find that the square-octagon lattice can support different phases, such as...