Electronic band-structure and optical constants of Pb2GeS4: Ab initio calculations and X-ray spectroscopy experiments

Vu, Tuan V.; Lavrentyev, A.A.; Gabrelian, B.V.; Ananchenko, L.N.; Parasyuk, O. V.; Karaim, Olha; Khyzhun, O.Y.

doi:10.1007/s10854-018-9698-4

Cited by 4 publications

(3 citation statements)

References 35 publications

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“…With that in mind, and with both end members of the series Sr 2‑x Pb x GeSe 4 being potential NLO materials, we set out to study this series in order to identify the structural changes in dependence of the Pb content along with their NLO properties. During our investigations, we uncovered a new, low temperature modification of Pb 2 GeSe 4 , which is isostructural to β-Pb 2 GeS 4 , adopting the centrosymmetric space group P 2 1 / c . Thus, we namedin analogy to the sulfidesthe high temperature NCS, from now on, as α-Pb 2 GeSe 4 and the new, low temperature form as β-Pb 2 GeSe 4 .…”

Section: Introductionmentioning

confidence: 76%

Effect of Pb Substitution in Sr_2-xPb_xGeSe₄ on Crystal Structures and Nonlinear Optical Properties Predicted by DFT Calculations

et al. 2020

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We investigated the Sr2‑xPb x GeSe4 series from 0 ≤ x ≤ 2 to study the impact of Pb on structure and properties. While the noncentrosymmetric (NCS) compounds γ-Sr2GeSe4 and α-Pb2GeSe4 have already been reported previously, the substitution variants Sr1.31Pb0.69GeSe4 (space group Ama2, a = 10.31220(1) Å, b = 10.39320(1) Å, c = 7.42140(1) Å) and Sr0.19Pb1.81GeSe4 (I4̅3d, a = 14.6177(3) Å) are introduced here for the first time. The experimentally determined optical band gaps decrease as predicted with increasing Pb content from γ-Sr2GeSe4 to Sr1.31Pb0.69GeSe4, Sr0.25Pb1.75GeSe4, and α-Pb2GeSe4 from 2.00, to 1.65, 1.45 and 1.42 eV, respectively. The nonlinear optical (NLO) properties of the orthorhombic compounds γ-Sr2GeSe4 and Sr1.3Pb0.7GeSe4 (approximated with the supercell “Sr3PbGe2Se8”) were studied both theoretically, using first-principle calculations, and experimentally. The calculations found the effective nonlinear susceptibility, d eff, of γ-Sr2GeSe4 and “Sr3PbGe2Se8” at the static limit to be 10.8 and 8.8 pm V–1, respectively. The experimental d eff values of γ-Sr2GeSe4, Sr1.31Pb0.69GeSe4, Sr0.25Pb1.75GeSe4, and α-Pb2GeSe4 were 2.6, 2.3, 0.68, and 0.79 pm V–1, respectively.

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Section: Introductionmentioning

confidence: 76%

Effect of Pb Substitution in Sr_2-xPb_xGeSe₄ on Crystal Structures and Nonlinear Optical Properties Predicted by DFT Calculations

et al. 2020

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“…So far, only two barium seleno-germanates have been reported, namely, Ba 2 GeSe 4 and Ba 2 Ge 2 Se 5 . , The former is a member of a diverse class of compounds with the general formula M II 2 TtQ 4 , where M II is either one or two different divalent cations, the tetrel Tt is a tetrahedrally coordinated cation such as Si, Ge, or Sn, and Q is a chalcogen atom such as S or Se. Exploratory search into M II – Tt – Q materials has been a reliable strategy for researchers to discover new compounds and new structure types. ,− Related materials are of interest in photovoltaic applications, including Ba 4 Ga 4 SnSe 12 and BaCu 2 SnS 4– x Se x . , Many of these compounds have been investigated for their nonlinear optical properties, in part because they are composed of noncentrosymmetric building blocks into the structure such as [ TtQ 4 ] 4– tetrahedra. − Although neither Ba 6 Ge 2 Se 12 (space group P 2 1 / c ) nor Ba 7 Ge 2 Se 17 ( Pnma ) crystallizes in a noncentrosymmetric space group, they adopt new structure types. Stoichiometric analogues containing Sr, Sn, or S could not be synthesized.…”

Section: Introductionmentioning

confidence: 99%

Ba₆Ge₂Se₁₂ and Ba₇Ge₂Se₁₇: Two Centrosymmetric Barium Seleno-Germanates with Polyatomic Anion Disorder

et al. 2022

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Herein, the crystal structures and physical properties of two previously unreported barium seleno-germanates, Ba 6 Ge 2 Se 12 and Ba 7 Ge 2 Se 17 , are presented. Ba 6 Ge 2 Se 12 adopts the P2 1 /c space group with a = 10.0903(2) Å, b = 9.3640(2) Å, c = 25.7643(5) Å, and β = 90.303(1)°, whereas Ba 7 Ge 2 Se 17 crystallizes in the Pnma space group with a = 12.652(1) Å, b = 20.069(2) Å, c = 12.3067(9) Å. Both structures feature polyatomic anion disorder: [Se 2 ] 2− in the case of Ba 6 Ge 2 Se 12 and [GeSe 5 ] 4− in the case of Ba 7 Ge 2 Se 17 . The anion disorder is verified by comparing pair distribution functions of ordered and disordered models of the structures. These anions are split unevenly across two possible sets of atomic coordinates. The optical band gaps obtained from the powdered samples are found to be 1.75 and 1.51 eV for Ba 6 Ge 2 Se 12 and Ba 7 Ge 2 Se 17 , respectively. Differential scanning calorimetry experiments indicate that the compounds are stable under the exclusion of air up to at least 673 K. The thermal diffusivity measurements revealed thermal conductivities reaching values as low as 0.33 W m −1 K −1 in both compounds at 573 K.

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“…The spin-orbital coupling (SOC) effect, 39 and the Hubbard parameter U 40,41 were also employed in the calculations as they play a very important role in a system with heavy elements likes Pb. [42][43][44][45][46][47][48][49][50][51]…”

Section: Introductionmentioning

confidence: 99%

Theoretical and experimental study on the electronic and optical properties of K_0.5Rb_0.5Pb₂Br₅: a promising laser host material

Lavrentyev

Gabrelian

et al. 2020

RSC Adv.

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Electronic band-structure and optical constants of Pb2GeS4: Ab initio calculations and X-ray spectroscopy experiments

Cited by 4 publications

References 35 publications

Effect of Pb Substitution in Sr_2-xPb_xGeSe₄ on Crystal Structures and Nonlinear Optical Properties Predicted by DFT Calculations

Effect of Pb Substitution in Sr_2-xPb_xGeSe₄ on Crystal Structures and Nonlinear Optical Properties Predicted by DFT Calculations

Ba₆Ge₂Se₁₂ and Ba₇Ge₂Se₁₇: Two Centrosymmetric Barium Seleno-Germanates with Polyatomic Anion Disorder

Theoretical and experimental study on the electronic and optical properties of K_0.5Rb_0.5Pb₂Br₅: a promising laser host material

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Electronic band-structure and optical constants of Pb2GeS4: Ab initio calculations and X-ray spectroscopy experiments

Cited by 4 publications

References 35 publications

Effect of Pb Substitution in Sr2-xPbxGeSe4 on Crystal Structures and Nonlinear Optical Properties Predicted by DFT Calculations

Effect of Pb Substitution in Sr2-xPbxGeSe4 on Crystal Structures and Nonlinear Optical Properties Predicted by DFT Calculations

Ba6Ge2Se12 and Ba7Ge2Se17: Two Centrosymmetric Barium Seleno-Germanates with Polyatomic Anion Disorder

Theoretical and experimental study on the electronic and optical properties of K0.5Rb0.5Pb2Br5: a promising laser host material

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Effect of Pb Substitution in Sr_2-xPb_xGeSe₄ on Crystal Structures and Nonlinear Optical Properties Predicted by DFT Calculations

Effect of Pb Substitution in Sr_2-xPb_xGeSe₄ on Crystal Structures and Nonlinear Optical Properties Predicted by DFT Calculations

Ba₆Ge₂Se₁₂ and Ba₇Ge₂Se₁₇: Two Centrosymmetric Barium Seleno-Germanates with Polyatomic Anion Disorder

Theoretical and experimental study on the electronic and optical properties of K_0.5Rb_0.5Pb₂Br₅: a promising laser host material