Two quaternary phosphides AIn_(3)Si_(4)P_(9)(A=Ca,1;Sr,2)belonging to the non-centrosymmetric space group P4_(1)2_(1)2 are discovered and synthesized through the solid-state method for the first time.They present extr...Two quaternary phosphides AIn_(3)Si_(4)P_(9)(A=Ca,1;Sr,2)belonging to the non-centrosymmetric space group P4_(1)2_(1)2 are discovered and synthesized through the solid-state method for the first time.They present extraordinary double-helix frameworks composed of corner-shared tetrahedral[InP_(4)]and[SiP_(4)]units.Although compounds 1 and 2 have undesirable band gaps(1.25 and 1.15 eV),their extremely low thermal expansion coefficients(∼10^(-6))result in high laser-induced damage thresholds approximately seven times that of benchmark AgGaS_(2)under a 2050 nm laser.Moreover,both compounds show weak second-harmonic generation intensities primarily caused by Kleinman forbidden nonlinear optical coefficients.Theoretical calculations further reveal that the electron transitions mainly originated from the tetrahedral[InP_(4)]and[SiP_(4)]units.展开更多
基金supported by the National Natural Science Foundation of China(21827813,21921001,22175172,22075283,92161125 and U21A20508)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2021300).
文摘Two quaternary phosphides AIn_(3)Si_(4)P_(9)(A=Ca,1;Sr,2)belonging to the non-centrosymmetric space group P4_(1)2_(1)2 are discovered and synthesized through the solid-state method for the first time.They present extraordinary double-helix frameworks composed of corner-shared tetrahedral[InP_(4)]and[SiP_(4)]units.Although compounds 1 and 2 have undesirable band gaps(1.25 and 1.15 eV),their extremely low thermal expansion coefficients(∼10^(-6))result in high laser-induced damage thresholds approximately seven times that of benchmark AgGaS_(2)under a 2050 nm laser.Moreover,both compounds show weak second-harmonic generation intensities primarily caused by Kleinman forbidden nonlinear optical coefficients.Theoretical calculations further reveal that the electron transitions mainly originated from the tetrahedral[InP_(4)]and[SiP_(4)]units.
