Polymorphism and Second Harmonic Generation in a Novel Diamond-like Semiconductor: Li2MnSnS4
Journal of Solid State Chemistry
Sulfide, Polymorphism, Stannite, Kesterite, SHG
High-temperature, solid-state synthesis in the Li2MnSnS4 system led to the discovery of two new polymorphic compounds that were analyzed using single crystal X-ray diffraction. The α-polymorph crystallizes in Pna21 with the lithium cobalt (II) silicate, Li2CoSiO4, structure type, where Z=4, R1=0.0349 and wR2=0.0514 for all data. The β-polymorph possesses the wurtz-kesterite structure type, crystallizing in Pn with Z=2, R1=0.0423, and wR2=0.0901 for all data. Rietveld refinement of synchrotron X-ray powder diffraction was utilized to quantify the phase fractions of the polymorphs in the reaction products. The α/β-Li2MnSnS4 mixture exhibits an absorption edge of ∼2.6–3.0 eV, a wide region of optical transparency in the mid- to far-IR, and moderate SHG activity over the fundamental range of 1.1–2.1 μm. Calculations using density functional theory indicate that the ground state energies and electronic structures for α- and β-Li2MnSnS4, as well as the hypothetical polymorph, γ-Li2MnSnS4 with the wurtz-stannite structure type, are highly similar.
Devlin, Kasey P.; Glaid, Andrew J.; Brant, Jacilynn A.; Zhang, Jian-Han; Srnec, Matthew N.; Clark, Daniel J.; Kim, Yong Soo; Jang, Joon I.; Daley, Kimberly R.; Moreau, Meghann A.; Madura, Jeffry D.; and Aitken, Jennifer A., "Polymorphism and Second Harmonic Generation in a Novel Diamond-like Semiconductor: Li2MnSnS4" (2015). Chemistry and Physics Faculty Articles. 175.