Floquet topological insulator in an optical lattice with modulated lattice depth

We propose a simple scheme to realize a Floquet topological insulator in an optical lattice by weakly modulating the lattice depth. When the modulation frequency resonantly couples the s and p bands, the Floquet Hamiltonian becomes topologically nontrivial. We map out the topological transition as a function of frequency and amplitude. We also confirm the bulk topology by finding edge states in a lattice with open boundary conditions. An advantage of our scheme is that the modulation amplitude can be relatively small, so the heating can be minimal.