Study on the defect of sulfur substituting for phosphorus in potassium dihydrogen phosphate

Abstract

The electronic structure and geometric distribution of neutral and charge states of the point defect sulfur substituting for phosphorus (Sp) in potassium dihydrogen phosphate (KH2PO4) have been investigated using a first-principles method. The energy gap is lowered to about 2.2 eV and 6.5 eV from the Density Function Theory (DFT) value of 7.3 eV by a -2 charge and neutral state, respectively. However, no defect states appear in the energy gap for the +1, -1, and +2 charge states of the Sp defect. The results show that the defects Sp with neutral and -2 charge states might contribute to the transient optical absorption under the high energy laser irradiation.