Rb2FeGe3S8 and Cs2FeGe3S8: New layered chalcogenides in A2MIIMIV3Q8 family with antiferromagnetic property

d6versus d10, Which Is Better for Second Harmonic Generation Susceptibility? A Case Study of K2TGe3Ch8 (T = Fe, Cd; Ch = S, Se)

“…As shown in Table S4, the SHG of many compounds within the II 2 II 1 IV 3 Ch 8 family was not measured. K 2 CdGe 3 S 8 possesses a better SHG response than compounds previously characterized in the II 2 II 1 IV 3 Ch 8 family. − The cation substitution within the II 2 II 1 IV 3 Ch 8 family greatly affects their crystal structures and nonlinear optical properties. − The SHG response of K 2 CdGe 3 Ch 8 (Ch = S, Se) is presented in Figure a. K 2 CdGe 3 S 8 and K 2 CdGe 3 Se 8 were revealed as type-I phase-matching materials, where the SHG intensity increases as particle size increases.…”

“…The refined atomic coordinates and selected important interatomic distances of K 2 CdGe 3 Ch 8 (Ch = S, Se) are summarized in Tables S2 and S3, respectively. Many previous studies have summarized the crystal structure of II 2 II 1 IV 3 Ch 8 (II = K, Rb, Cs; II = Mn, Co, Fe, Zn, Cd; IV = Ge, Sn; and Ch = S, Se). − K 2 CdGe 3 Ch 8 (Ch = S, Se) are the newest members of the II 2 II 1 IV 3 Ch 8 family. To simplify the discussion, K 2 CdGe 3 S 8 was selected to present the crystal structure of K 2 CdGe 3 Ch 8 (Ch = S, Se).…”

“…To enhance SHG coefficients, some strategies such as incorporating elements with a stereoactive lone electron pair − and a conjugated structure motif − have proved effective. In the contrast, the elements that needed to be avoided would be elements with d–d transitions present. − In this work, we reported an acentric chalcogenide system of K 2 TGe 3 Ch 8 (T = Fe, Cd; Ch = S, Se), which provides a good platform for studying how d electron configuration affects SHG coefficients. K 2 CdGe 3 S 8 and K 2 CdGe 3 Se 8 are new members of the II 2 II 1 IV 3 Ch 8 (II = K, Rb, Cs; II = Mn, Co, Fe, Zn, Cd; IV = Ge, Sn; and Ch = S, Se) family. − K 2 CdGe 3 S 8 and K 2 CdGe 3 Se 8 are isostructural to K 2 FeGe 3 S 8 .…”

“…In the contrast, the elements that needed to be avoided would be elements with d–d transitions present. − In this work, we reported an acentric chalcogenide system of K 2 TGe 3 Ch 8 (T = Fe, Cd; Ch = S, Se), which provides a good platform for studying how d electron configuration affects SHG coefficients. K 2 CdGe 3 S 8 and K 2 CdGe 3 Se 8 are new members of the II 2 II 1 IV 3 Ch 8 (II = K, Rb, Cs; II = Mn, Co, Fe, Zn, Cd; IV = Ge, Sn; and Ch = S, Se) family. − K 2 CdGe 3 S 8 and K 2 CdGe 3 Se 8 are isostructural to K 2 FeGe 3 S 8 . K 2 CdGe 3 S 8 and K 2 CdGe 3 Se 8 possess superior nonlinear optical (NLO) properties compared to K 2 FeGe 3 S 8 .…”

“…K 2 CdGe 3 S 8 and K 2 CdGe 3 Se 8 are type-I phase-matching materials. K 2 CdGe 3 S 8 exhibits balanced NLO properties of a high SHG coefficient (2.1× AgGaS 2 , samples of particle size of 200–250 μm), high LDTs (6.2× AgGaS 2 ), and good air stability and is the record holder of best SHG properties in the II 2 II 1 IV 3 Ch 8 (II = K, Rb, Cs; II = Mn, Co, Fe, Zn, Cd; IV = Ge, Sn; and Ch = S, Se) family. − The superior SHG response of K 2 CdGe 3 S 8 is attributed to the chemical characteristics of Cd compared to Fe, which was studied in this work. A detailed study of crystal structures, electronic structures, optical properties, and density functional theory (DFT) calculations of K 2 TGe 3 Ch 8 (T = Fe, Cd and Ch = S, Se) is summarized in the present work.…”