MgSiAs: An Unexplored System with Promising Nonlinear Optical Properties

Abstract

Two new non-centrosymmetric ternary compounds, MgSiAs 2 and Mg 3 Si 6 As 8 , are discovered via metal flux and solid-state synthetic methods. MgSiAs 2 belongs to the well-known II-IV-V 2 family, which is extensively studied experimentally and computationally for their optical properties. MgSiAs 2 is computationally predicted but not experimentally known prior to this work. Mg 3 Si 6 As 8 crystallizes in a new non-centrosymmetric cubic chiral structure type with the Pearson symbol cP68. The syntheses, crystal structure, thermal and chemical stabilities, electronic structures, and optical properties of these two new compounds are investigated in this work. Optical absorption measurements and electronic structure calculations reveal the two compounds to be direct or pseudo-direct bandgap semiconductors (1.8-2 eV). The crystal structures of both compounds are non-centrosymmetric, though Mg 3 Si 6 As 8 belongs to the 432 chiral crystal class, which is optically active but does not exhibit second harmonic generation (SHG) behavior. The SHG response of MgSiAs 2 is 60% of that for AgGaS 2 , but MgSiAs 2 exhibits a higher laser damage threshold than AgGaS 2 at 33.2 MW cm −2 .

Crystal and Electronic Structure and Optical Properties of AE2SiP4 (AE = Sr, Eu, Ba) and Ba4Si3P8

“…Ternary tetrel‐pnictides with cations other than Li, in A ‐ Tt ‐ Pn systems ( A = electropositive cation; Tt = Si, Ge; Pn = P, As), have been intensively investigated, though . Tetrel‐pnictide frameworks have shown great diversity in terms of their crystal structures, ranging from zero‐dimensional isolated TtPn 4 tetrahedra ( A 4 Tt P 4 ; A = Ca, Sr, Ba; Tt = Si, Ge), one‐dimensional chains (K 2 SiP 2 , Ca 3 Si 2 P 4 ), two‐dimensional layers (Li 2 SiP 2 , Ca 2 Si 2 P 4 , Li 1– x Sn 2+ x As 2 ), to three‐dimensional frameworks (MgSiAs 2 , Mg 3 Si 6 As 8 , Ca 3 Si 8 P 14 ) , , . The major building unit in these compounds is the TtPn 4 tetrahedron, which can be connected via corner‐ and edge‐sharing, and via homoatomic Pn–Pn bonds (Figure ).…”

“…The major building unit in these compounds is the TtPn 4 tetrahedron, which can be connected via corner‐ and edge‐sharing, and via homoatomic Pn–Pn bonds (Figure ). Some of the produced crystal structures are noncentrosymmetric, for example the II‐IV‐V 2 chalcopyrite family (II = Mg, Zn, Cd; IV = Si, Ge, Sn; V = P, As, Sb), leading to their intensive study for nonlinear optical applications , …”

“…Our group has recently synthesized the first compounds in the Mg‐Si‐As system, MgSiAs 2 and Mg 3 Si 6 As 8 . In 2015, three new Ca‐Si‐P compounds were reported by Zhang et al Our work was inspired by the numerous structural arrangements displayed by Ca‐Si‐P systems and Si‐P frameworks in general (Figure ) coupled with the lack of known alkaline‐earth silicon phosphides.…”

Flux Growth of Phosphide and Arsenide Crystals

“…The technology aspect of the crystal growth is in its "trial and error" nature, which requires multiple attempts sometimes guided by the grower's intuition. In situ studies of the flux growth have provided insights regarding the structure of the liquid phase and cascades of solid-solid transformation occurring during heating and cooling (Shoemaker et al, 2014;Woo et al, 2018).…”

“…The volatility of P and As has resulted in poor exploration of many metal-phosphorus (arsenic) phase diagrams in the areas of high pnictogen content. Nevertheless, compounds with substantial P(As) content often exhibit interesting chemistry and useful practical properties, with potential applications as heat conductors, thermoelectrics, catalysts, and non-linear optical materials (Soheilnia et al, 2007;Lindsay et al, 2013;Dolyniuk et al, 2017;Nuss et al, 2017;Pöhls et al, 2017;Li et al, 2018;Owens-Baird et al, 2018, 2019Woo et al, 2018;Coleman et al, 2019;Mark et al, 2019;Yu et al, 2019).…”