Fig. 3: The two-band and three-band contributions to the second harmonic generation (SHG) susceptibility compared with the interband Berry curvature dipole (BCD).
From: Second harmonic Hall responses of insulators as a probe of Berry curvature dipole
a The monolayer h-BN, in which the B-N bond lengths are extended by Δd in the y-direction. The single (double) lines represent the long (short) bonds of the strained h-BN. b The comparison of 2-band and 3-band transition terms of SHG susceptibility spectra with the interband BCD for gradually increasing Δd values. c The un-strained h-BN, whose symmetry is adjusted by the static electric field bias of strength Eb in the y-direction (the thick red arrow). d The same as b with varying Eb values.
