Fig. 2: B1u phonon mode and Weyl bands.
From: Robust and tunable Weyl phases by coherent infrared phonons in ZrTe5
a–c Band structure along W1-Γ-W2 direction for different Q values corresponding to the B1u-4 phonon mode. W1 and W2 are the sink and source of the Berry curvature separated along the ky direction (panel g). The inset in (a) shows the ground state bands (i.e., Q = 0) in the vicinity of the Γ-point along with the Te3 (red dots) and Te2 (blue dots) band characters. d Charge density plot of the HOMO and LUMO states at the Γ point showing the transfer of charge from Te2 to Te3 atoms for nonzero Q. e, f 2D bands forming the WPs on the kx-ky (ka-kb) plane for different Q values. Note that the finite gaps seen in the Weyl bands are due to the finite k-point mesh in the calculation. The presence of Weyl points was confirmed by calculating the topological charges. g Evolution of the WPs as a function of Q. ±1 indicates the chirality of the WPs. h Energy difference per formula unit as a function of Q showing the harmonic regime. The blue dots in (h) highlight different Q values studied in the previous figures.
