Structural stress and extra optical absorption induced by the intrinsic cation defects in KDP and ADP crystals: a theoretical study

Abstract

VP5− defects are regarded as one of the main sources for the initial structural breakdown in KDP compared with ADP.

Hybrid density functional theory calculations for the electronic and optical properties of Fe3+-doped KDP crystals

“…To study the effect of Fe 3+ ions on the crystal structure of KDP, the change gradients of the O–H and P–O bonds were calculated as follows: 32 where D (defect state) represents the bond lengths in the defective systems, D (pristine system) represents the bond lengths in the pristine system, and Δ is the absolute value of the gradient. The results are shown in Fig.…”

“…The electronic wave functions were expanded as plane waves using an energy cutoff of 680 eV. [29][30][31][32] The electron exchange and correlation (XC) functional of the generalized gradient approximation (GGA) 33,34 functional of Perdew-Burke-Ernzerhof (PBE) 35,36 was used to optimize the configurations, and the force convergence criterion for structural relaxation was set to 0.01 eV Å −1 . 21 The energetic, electronic and optical properties were analyzed using the Heyd-Scuseria-Ernzerhof (HSE06) [37][38][39] hybrid functional system.…”

Electron paramagnetic resonance spectroscopy and first-principles calculations of Cr3+ doped KDP crystals

“…The deformation induced in the cell by point defects cannot be disregarded. Thus, we looked at how the O–H and P–O bond length in KDP crystals varied with the distance from the centre of the point defect when Cr atoms replaced K atoms in different charge states, with the variation described as: 25 where D (defect state) and D (pristine system) represent the bond lengths of the KDP crystals with and without defects, respectively, and Δ are the absolute values of the gradient.…”

Deep-UV optical properties of KDP-family crystals: a comprehensive characterization

“…The main reason is that there may be more impurities in 70% deuterated KDP crystal than in the KDP and DKDP crystals. For the crystals grown in aqueous solutions, such as KDP-family crystals, the presence of growth defects (including intrinsic point defects, scattering particles, and impurity ions) can cause rather absorptions in the UV waveband 40,[43][44][45][46][47][48][49][50][51][52][53][54] . The typical intrinsic point defects in KDP-family crystals include H i , V P , V K , and V N .…”

“…The typical intrinsic point defects in KDP-family crystals include H i , V P , V K , and V N . Especially V 5− P defect, it is regarded as one of the most destructive intrinsic point defects in KDP crystal, which could introduce a strong defect state in the band gap of KDP and cause extra optical absorption at 310-620 nm 49,50 . For the Scattering particles in KDP-family crystals, they can significantly reduce the optical quality of the crystal 51,52 , and the scattering particles can cause the light loss in the whole transmission wavebands of the crystals.…”