Band structure evolution from kagome to Lieb under periodic driving field

Abstract

We theoretically investigate the light-induced transition of the kagome quasienergy spectrum into a Lieb-like spectrum under periodic driving fields. We develop a general framework for calculating renormalized hopping potentials, which is applicable to any two-dimensional lattice with arbitrary field polarizations. By implementing this framework on a kagome lattice driven by a linearly polarized light in the off-resonant regime, we demonstrate that the hopping strength along specific bonds can be tuned to zero. This control leads to the merging of two inequivalent Dirac points in the Brillouin zone, governed by the field parameters. This merging leads to the transition from the kagome quasienergy spectrum to a Lieb-like spectrum with a smaller bandwidth at a specific value of field parameter. In addition, the longitudinal optical conductivity of the driven kagome lattice can be measured to investigate the kagome to Lieb transition and merging of Dirac points, as suggested by our calculation.