Pb_0.65Mn_2.85Ga₃S₈ and Pb_0.72Mn_2.84Ga_2.95Se₈: Two Quaternary Metal Chalcognides with Open-Tunnel-Framework Structures Displaying Intense Second Harmonic Generation Responses and Interesting Magnetic Properties

Abstract

By combining different nonlinear optical-active structural chromophores with transition metal Mn into a crystal structure, two novel quaternary metal chalcogenides PbMnGaS (1) and PbMnGaSe (2) were successfully synthesized. Compounds 1 and 2 are isostructural, and they represent a new structure type that crystallizes in the space group P6̅ (No. 174) in the hexagonal system. Their structures feature an interesting three-dimensional open-tunnel framework composed of bridged infinite chains with Pb cations filling in the biggest tunnels. Interestingly, both 1 and 2 demonstrate intense second harmonic generation responses at 2.09 μm that is about 1.5 and 4.4 times, respectively, of that of the benchmark material AgGaS. However, 1 and 2 possess different optical diffuse reflectance spectra: 1 displays an evident multiband absorption characteristic with two distinguishing absorption edges of 738 and 551 nm, corresponding to two band gaps of 1.68 and 2.25 eV, respectively, while 2 exhibits only one sharp edge, and the corresponding band gap was estimated to be 1.65 eV. Moreover, apart from the considerable structural similarity between 1 and 2, the dc temperature dependent susceptibility measurements indicate that compound 1 is paramagnetic, while compound 2 exhibits spin-glass-like behavior.

Sn2Ga2S5: A Type of IR Nonlinear-Optical Material

“…Because divalent Sn and Pb have coordination preferences and ionic radii similar to those of AE metals, in most cases, the lattice sites of AE in AE chalcogenides can be occupied by Sn and Pb atoms. This character has been verified by the discovery of many Pb 2+ /Sn 2+ -MQ 4 type MIR NLO materials. − Therefore, Pb 2+ /Sn 2+ chalcogenides also have high opportunities as new MIR NLO materials.…”

Recent Achievements in Lone-Pair Cation-Based Infrared Second-Order Nonlinear Optical Materials

“…Stimulated by a possible synergistic effect from different acentric structural units and inspired by the idea that the introduction of transition metals can increase the compositional flexibility, Pb 0.72 Mn 2.84 Ga 2.95 Se 8 and Pb 0.65 Mn 2.85 Ga 3 S 8 have been synthesized and studied with NLO activities …”

“…(a, b) Crystal structure of Pb 0.65 Mn 2.85 Ga 3 S 8 . Reprinted with permission from ref . Copyright 2017 American Chemical Society.…”

“…95 Se 8 and Pb 0.65 Mn 2.85 Ga 3 S 8 have been synthesized and studied with NLO activities. 104 They are isomorphic and crystallized with the hexagonal P6 structure. The structure of Pb 0.65 Mn 2.85 Ga 3 S 8 will be described as a representative.…”

Perovskite-like Framework Encapsulated with Fe-Based Magnetic Units in Ba10Fe3Sb7Se24

“…Currently, to the best of our knowledge, multinary metal chalcogenides characterized with both magnetic and nonlinear optical properties are limited to Li 2 MGeS 4 (M = Mn, Co), 17 Pb 0.72 Mn 2.84 Ga 2.95 Se 8 (Q = S, Se), 18 and K 2 MnGe 3 Se 8 . 19 The photon absorption along with electronic transition can be forbidden for Mn 2+ ions in these structures 20 and, therefore, does not affect the SHG intensity.…”