Fig. 4: Quench-induced topological band inversion and Berry curvature dipole (BCD) peaks.
a1–c1 Floquet energy bands (Eq. (22)) for the ky = 0 slice. In (a1) where T1 = 0.1T2 and (c1) where T2 = 0.1T1, the \({{{{\mathcal{H}}}}}_{2}({{{\bf{k}}}})\) with light amplitude \({A}_{0}=\sqrt{2}{A}_{0c}\) and \({{{{\mathcal{H}}}}}_{1}({{{\bf{k}}}})\) with A0 = 0 are respectively dominant. They respectively correspond to the normal insulator (NI) and Chern insulator (CI) phases and are both gapped (pale yellow). But in (b1) where T1 = T2, nontrivial contributions from \({{{{\mathcal{H}}}}}_{1}({{{\bf{k}}}})\) and \({{{{\mathcal{H}}}}}_{2}({{{\bf{k}}}})\) cancel each other out, leaving a gapless band structure. a2–c2 Berry curvature (Eq. (13)) of the lower band, whose integral over the kx-ky plane interpolates between the quantized values of 0 and + 1 as T1/T2 increases. a3-c3 The corresponding Hall conductance (Eq. (9)), which exhibits these quantized values when EF is within the band gap (pale yellow). a4–c4 The BCD (Dxz) (Eq. (10)), which vanishes for EF within the band gap but which peaks at the band edges, particularly when T1 = T2. The other parameters are identical to those in Fig. 1. Here, T2 is fixed at 0.1ℏ/eV ≈ 6.58212 × 10−17 s.
