The Fe3+ ion is the most common impurity ions in potassium dihydrogen phosphate (KDP) and it can combine with hydrogen vacancies to form cluster defects which may lead to optical...

Defects are considered as one of the important factors affecting the quality and laser-induced damage threshold of potassium dihydrogen phosphate (KH 2 PO 4 , KDP). In this study, hybrid density functional theory is used to investigate how the Zn 2+ ions affect the properties of KDP crystal. Since crystal defects often do not exist singly but combine with each other to form clusters, two charge-compensated defect clusters, Zn K + (Zn 2+ ion substitutes K + ion)+ V K − (potassium vacancy)and Zn K + + V H − (hydrogen vacancy) are modeled in this work to investigate the stability of them, the defect states induced by these defects and the mechanisms of the structural breakdown. Zn 2+ ions have a slight effect on the electronic property and linear optical absorption of KDP crystal. With the increase of Zn 2+ concentration, more defect pairs are generated, which causes the deformation of more O─H bonds linking to PO 4 and then the crystal structure becomes unstable. The laser-induced damage resistance of the KDP crystalis affected due to the instability of crystal structure.