LiMg(IO3)3: an excellent SHG material designed by single-site aliovalent substitution

An excellent second harmonic generation (SHG) material, LiMg(IO3)(3) (LMIO), has been elaborately designed from Li2MIV(IO3)(6) (M-IV = Ti, Sn, and Ge) by aliovalent substitution of the central M-IV cation followed by Wyckoff position exchange. The new structure sustains the ideal-alignment of (IO3)(-) groups. Importantly, LMIO exhibits an extremely strong SHG effect of roughly 24 x KH2PO4 (KDP) under 1064 nm laser radiation or 1.5 x AgGaS2 (AGS) under 2.05 mu m laser radiation, which is larger than that of alpha-LiIO3 (18 x KDP). The replacement of M-IV with Mg2+ without d-d electronic transitions induces an obviously larger band gap (4.34 eV) with a short absorption edge (285 nm). This study shows that single-site aliovalent substitution provides a new synthetic route for designing SHG materials.