Full bandstructure calculation of second harmonic generation susceptibility of $\alpha-LiIO_{3}$ crystal

Abstract

The present work performs full bandstructure calculations to investigate the structural effect and the transition mechanisms of the second harmonic generation (SHG) susceptibility of the $\alpha-LiIO_{3}$ crystal. The anomalous inconsistency of associated experimental data of the SHG susceptibility tensor is elucidated to be dominated by the structural effect especially on the topology of $O$-atoms. On the manipulation of the structural effect, the modification of SHG susceptibility using an external pressure is simulated. The calculations of SHG susceptibility tensor are completed at finite frequencies and the static limit. The comparison with the experiments is also incorporated. On the analysis of the transition mechanisms, the inter-band transition is determined to entirely dominate the whole SHG susceptibility at the static limit; however, the effect of the intra-band motion is revealed to be as important as that of the inter-band transition at finite frequencies.