Multifunctional Cu₂TSiS₄ (T = Mn and Fe): Polar Semiconducting Antiferromagnets with Nonlinear Optical Properties

Abstract

Cu2TSiS4 (T = Mn and Fe) polycrystalline and single-crystal materials were prepared with high-temperature solid-state and chemical vapor transport methods, respectively. The polar crystal structure (space group Pmn21) consists of chains of corner-sharing and distorted CuS4, Mn/FeS4, and SiS4 tetrahedra, which is confirmed by Rietveld refinement using neutron powder diffraction data, X-ray single-crystal refinement, electron diffraction, energy-dispersive X-ray spectroscopy, and second harmonic generation (SHG) techniques. Magnetic measurements indicate that both compounds order antiferromagnetically at 8 and 14 K, respectively, which is supported by the temperature-dependent (100–2 K) neutron powder diffraction data. Additional magnetic reflections observed at 2 K can be modeled by magnetic propagation vectors k = (1/2,0,1/2) and k = (1/2,1/2,1/2) for Cu2MnSiS4 and Cu2FeSiS4, respectively. The refined antiferromagnetic structure reveals that the Mn/Fe spins are canted away from the ac plane by about 14°, with the total magnetic moments of Mn and Fe being 4.1(1) and 2.9(1) μB, respectively. Both compounds exhibit an SHG response with relatively modest second-order nonlinear susceptibilities. Density functional theory calculations are used to describe the electronic band structures.

BaCu2SiS4: A New Member of the AIIBI2MIVQ4 Chalcogenide Family with a Chiral Crystal Structure

“…This result is comparable to BaCu 2 SnS 4 (P3 2 21) where the VBM mostly consisted of Cu-d and S-p orbitals. [44] FeCu 2 SiS 4 Pmn2 1 1.52 [85] FeAg 2 GeSe 4 Pmn2 1 [88] MnLi 2 GeS 4 Pna2 1 3.07 [60] α-MnLi 2 SnS 4 Pna2 1 2.60 2.30 [57] ZnLi 2 SiS 4 Pna2 1 3.90 3.17 [89] α-ZnLi 2 GeS 4 Pna2 1 4.07 3.11 [61] CdLi 2 GeS 4 Pna2 1 3.15 [43] CdLi 2 GeSe 4 Pna2 1 2.50 1.98 [90] CdLi 2 SnSe 4 Pna2 1 2.20 2.11 [90] CdAg 2 GeS 4 Pna2 1 2.32 [91] HgLi 2 GeSe 4 Pna2 1 2.27 1.69 [92] HgLi β-SrCu 2 SnS 4 Ama2 2.06 1.14 [95] SrCu 2 GeSe 4 Ama2 0.70 [96] BaCu 2 SnSe 4 Ama2 1.72 1.07 [44] CdLi 2 SnS 4 Pmmn [56] BaAg 2 SnS 4 I222 1.77 0.48 [52] BaAg 2 GeSe 4 I222 1.57 0.69 [47,96] BaAg 2 SnSe 4 I222 1.42 0.61 [47] MnCs 2 SnSe 4 Fddd 1.90 1.54 [68] MnCs 2 SnTe 4 Fddd [97] α-FeCu 2 SnS 4 P4 [98] FeAg 2 GeS 4 I4…”

Crystal Growth of Quaternary AkRE2Si2S8 (Ak = Ca and Sr; RE = La–Tb) Thiosilicates Using Flux-Assisted Boron Chalcogen Mixture Method: Exploring X-ray Scintillation, Luminescence, and Magnetic Properties

“…Complex metal chalcogenides are well-known for their structural diversity and extensive physical properties and, consequently, their synthesis has been widely explored. − As a class, chalcogenides are more polarizable than oxides and also exhibit a tendency to self-catenate, often leading to relatively complex structures that exhibit interesting electronic structures and functionalities. , Lanthanide-containing chalcogenides, in particular, have garnered attention for their capacity to form intricate ternary and quaternary compounds, as have many main group and transition element-containing compositions. These novel structures of metal chalcogenides have paved the way for numerous applications, including thermoelectrics, photovoltaics, optics, optoelectronics, magnetism, photoluminescence, nonlinear optics, and scintillation …”

Melilite oxychalcogenide Sr2FeGe2OS6: a phase-matching IR nonlinear optical material realized by isomorphous substitution

“…K 2 FeGe 3 S 8 exhibits a large E g (2.1 eV) and a small d eff (0.25 × AgGaS 2 ). Recently, Cu 2 FeSiS 4 with antiferromagnetic and weak SHG susceptibility has been reported by Tan's group, 33 which crystallizes in Pmn 2 1 (no. 31) and displays a wurtzite structure composed of hexagonally close packed S and inserted metal ions.…”

“…[15][16][17] More than one thousand Fe-based NCS compounds of various types have been reported in the past century, for example, chalcogenides (e.g., FeMo 2 S 4 , 18 Cu 1.068 Fe 1.068 S 2 19 ), oxides (e.g., FeGaO 3 , 20 BiFeO 3 21 ), phosphides (e.g., LaFe x Co 2−x P 2 , 22 An 2 Fe 12 P 7 (An = U, Th) 23 ), halides (e.g., Na 2 Fe 2 F 7 , 24 LiMnFeF 6 25 ), and oxyhalides (e.g., CaFeO 2 Cl, 26 KFe(C 2 O 4 )F 27 ). However, two-or multi-photon absorption is a frequent occurrence because of their narrow band gaps (E g < 2.0 eV), 28,29 33 which crystallizes in Pmn2 1 (no. 31) and displays a wurtzite structure composed of hexagonally close packed S and inserted metal ions.…”