Floquet Chern Vector Topological Insulators in Three Dimensions

We theoretically and numerically investigate Chern vector insulators and topological surface states in a three-dimensional lattice, based on phase-delayed temporal-periodic interactions within the tight-binding model. These Floquet interactions break time-reversal symmetry, effectively inducing a gauge field analogous to magnetic flux. This gauge field results in Chern numbers in all spatial dimensions, collectively forming the Chern vector. This vector characterizes the topological phases and signifies the emergence of robust surface states. Numerically, we observe these states propagating unidirectionally without backscattering on all open surfaces of the three-dimensional system. Our work paves the way for breaking time-reversal symmetry and realizing three-dimensional Chern vector topological insulators using temporal-periodic Floquet techniques.