Theoretical Analysis of Electronic Structure and Optical Properties of Potassium Dihydrogen Phosphate Crystal Affected by [011] Screw Dislocation

Abstract

The atomic configurations, energetics, electronic structures, and optical properties of [011] screw dislocation in the KDP crystal have been analyzed by using density functional theory with Perdew–Burke–Ernzerhof and HSE06 functionals. The results have confirmed that the [011] screw dislocation reduces the band gap and introduces the intermediate states into the forbidden gap, which are principally derived from 2p (O)–3p (P) hybridization. Extra optical absorption peaks are also introduced at 170, 220, and 270 nm, which may be attributed to the dehydration process, and PO2 radical emerged near the dislocation core in the KDP crystal. The [011] screw dislocations will contribute to a large nonlinear absorption, enhance the crystal to absorb more laser energy, and decrease the laser-induced damage threshold of the KDP crystal. These findings will also contribute to our understanding of the root of the extra 270 nm absorption peak in practice and provide a basis for methods to improve laser-induced damage threshold of KDP or DKDP in frequency conversion devices.

Progress on deuterated potassium dihydrogen phosphate (DKDP) crystals for high power laser system application

“…As the most common defects in KDP/DKDP crystals, we also studied the effect of dislocation by theoretical modeling. The structure, total system energies, electronic structures, and optical absorption of the [010] and [011] screw dislocations in KDP crystals have been investigated using the density functional theory with Perdew-Burke-Ernzerhof and Heyd-Suseria-Ernzerhof (HSE06) functionals 109 , 110 . The results show that these dislocations would contribute to a large nonlinear absorption, enhance the crystal to absorb more laser energy, and decrease the laser-induced damage threshold of the KDP crystal.…”

Epitaxy of Antimonene Thin Films with Screw Dislocations for the Application of Saturable Absorbers

“…Screw dislocations are a type of defect that breaks the space reversal symmetries in the lattice and, consequently, alters the coupling in the stacking layers, emerging with attractive prospects in acoustics, catalysis, and optics. , Lately, Peng et al proved that screw dislocations in Cu can move supersonically, and the motion of a dislocation is determined by the resolved shear stress . As the electrocatalytic activity correlates linearly with the number of reaction sites, screw dislocations can serve as efficient catalysts toward the hydrogen evolution reaction. − The spiral structures of screw dislocations exhibit high edge-to-surface ratios that can accommodate abundant active sites in nonlinear absorption (NLA), which contributes to generating ultrafast pulses with a broad waveband as well as low laser-damaged threshold, thereby making them ideal candidates in mode-locked fiber lasers. − Hence, the synthesis of spiral β-Sb with diverse stacking behaviors and its NLA properties favors great hidden potential, whereas relevant studies are rarely addressed.…”