A High Laser Damage Threshold and a Good Second-Harmonic Generation Response in a New Infrared NLO Material: LiSm3SiS7

Abstract

A series of new infrared nonlinear optical (IR NLO) materials, LiRe 3 MS 7 (Re = Sm, Gd; M = Si, Ge), have been successfully synthesized in vacuum-sealed silica tubes via a high-temperature solid-state method. All of them crystallize in the non-centrosymmetric space group P6 3 of the hexagonal system. In their structures, LiS 6 octahedra connect with each other by sharing common faces to form infinite isolated one-dimensional ∞ [LiS 3 ] n chains along the 6 3 axis. ReS 8 polyhedra share edges and corners to construct a three-dimensional tunnel structure with ∞ [LiS 3 ] n chains located inside. Remarkably, LiSm 3 SiS 7 shows promising potential as one new IR NLO candidate, including a wide IR transparent region (0.44-21 µm), a high laser damage threshold (LDT) (3.7 × benchmark AgGaS 2 ), and a good NLO response (1.5 × AgGaS 2 ) at a particle size between 88 µm and 105 µm. Dipole-moment calculation was also used to analyze the origin of NLO responses for title compounds.

Structure Determination and Luminescent Property Studies of the Single Crystal Na3Sm(BO3)2

“…In this method, the reactant materials are completely dissolved in molten salt to obtain a uniform liquid, and a single crystal with large size can then be obtained by limiting the number of nuclei formed during cooling. Up to now, many mixed-metal oxides, sulfides, and complex intermetallics have been successfully obtained using this method [10][11][12][13]. We think the Na 2 O-B 2 O 3 system can be used as a good flux for the low melting point (700~900 • C) and powerful dissolving capacity for many oxides, including refractory rare-earth oxides.…”

Synthesis-enabled exploration of chiral and polar multivalent quaternary sulfides

“…Replacing monovalent Au with monovalent Li results in La6Li2Si2S14, where Li + occupies the centers of the octahedra (LiS6) instead of on the faces (AuS3), due to the size difference between Li and Au. 28,56 Table 1. Reported values of metal-sulfur bond lengths for select binary and ternary sulfides.…”

“…(RE)6(TM)x(Tt)2Q14 quaternary system is extensively studied for germanium-selenium analogues, bacause those phases for the most part can be synthesized from elements. 21,22,24,25,27,28,75 For Sicontaining systems, the typical synthesis from elements at a temperature of ~1000 o C resulted in poor yield of the quaternary compounds as products are dominated by binary and ternary sulfides.…”

“…One such complex system is a class of quaternary sulfides of type (RE)6(TM)x(Tt)2Q14 (RE = rare-earth metal; TM = transition metals; Tt = Si, Ge, and Sn; Q = S and Se) also referred as (RE)3(TM)x/2(Tt)Q7. While in the present manuscript we focus only on transition metals, it should be noted that the role of the transition metal can be fulfilled by several main group metals, such as Li, Al, Sb, In, and Ga. [10][11][12][13][14] (RE)6(TM)xSi2S14 (x = 1 and 2) phases for several rare-earth and transition metals were first mentioned in a 1969 paper by Michelet and Flahaut, where the authors used a reaction of binary sulfides at high temperatures (1350 o C) 15,16 . The majority of later manuscripts focused on the crystal structures of Ge and Sn analogues with TM = Mn-Cu where syntheses from elements provide good yields of the target quaternary sulfides.…”

“…While several of the aforementioned papers analyzed the magnetic properties of selected (RE)6(TM)x(Tt)2Q14, many other papers explored the non-linear optical properties of similar compounds where the transition metal was replaced with Ga or Li: La6Ga(Ge/Ga)S14 27 and Sm6Li2Si2S14 28 . The variety of all possible combinations of rare-earth and transition metals, tetrels (Si, Ge, and Sn), and chalcogenides (S and Se), gives rise to a remarkable number of almost 2,000 quaternary phases (not counting solid-solutions), providing a broad avenue for property tuning and allowing computational explorations via machine-learning methods or high-throughput calculations.…”