Figure 5.

SSH2D with nanoparticles: 2D extension of the SSH model in an array of nanospheres, where a is the radius of the nanoparticle, d is the unit cell width, and t = βd/2 is the intracell length. Interaction strengths can be tuned by contracting/expanding the square formed by the positions of the four nanoparticles in the unit cell, i.e., by changing β. This leads to two different topological regimes: a trivial phase for β < 1 and a nontrivial phase for β > 1.