Time-dependent Gutzwiller simulation of Floquet topological superconductivity

Periodically driven systems provide a novel route to control the topology of quantum materials. In particular, Floquet theory allows an effective band description of periodically-driven systems through the Floquet Hamiltonian. Along this direction, it was theoretically predicted that d-wave cuprate superconductors irradiated with circularly-polarized light (CPL) exhibit Floquet topological superconductivity purely from the many-body effect by employing the high frequency expansion (HFE) and deriving Floquet t–J model [Kitamura and Aoki, Commun. Phys. (2022)]. Here, we study the time evolution of d-wave superconductors irradiated with CPL [Anan et al., arXiv: 2309.06069]. We observe the development of the id_xy-wave pairing amplitude along with the original d_x²−y²-wave order upon gradual increasing of the field amplitude, owing to the three-site term with broken time-reversal symmetry. We further numerically construct the Floquet Hamiltonian for the steady state, with which we identify the system as the fully-gapped d+id-wave superconducting phase with a nonzero Chern number. We explore the low-frequency regime where the HFE breaks down, and find that the topological gap of an experimentally-accessible size can be achieved at much lower laser intensities.