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Baranets S, Ovchinnikov A, Bobev S. Synthesis, crystal and electronic structure of BaLi 2Cd 2Ge 2. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2021. [DOI: 10.1515/znb-2021-0114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
A new quaternary germanide has been synthesized and structurally characterized. BaLi2Cd2Ge2 adopts the rhombohedral CaCu4P2 structure type (Pearson code hR7; space group
R
3
‾
m
$R‾{3}m$
, Z = 3) with unit cell parameters a = 4.5929(6) and c = 26.119(5) Å. Structure refinements from single-crystal X-ray diffraction data demonstrate that the layered crystal structure can be regarded as an ordered quaternary variant of the ternary archetype; structural parallels to layered pnictides and binary germanides can also be drawn. The layered crystal structure is characterized by the absence of direct Ge–Ge and Cd–Cd homoatomic bonds, which suggests that BaLi2Cd2Ge2 should be classified as a Zintl phase, according to the formulation (Ba2+)(Li+)2(Cd2+)2(Ge4−)2. Electronic structure calculations show that the Fermi level crosses a distinct peak in the DOS, although the presence of an electronic band gap or a dip in the electronic density of states at the Fermi level is expected based on the electron partitioning.
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Affiliation(s)
- Sviatoslav Baranets
- Department of Chemistry and Biochemistry , University of Delaware , Newark , DE , 19716 , USA
| | - Alexander Ovchinnikov
- Department of Materials and Environmental Chemistry , Stockholm University , Stockholm , 10691 , Sweden
| | - Svilen Bobev
- Department of Chemistry and Biochemistry , University of Delaware , Newark , DE , 19716 , USA
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Ogunbunmi MO, Baranets S, Childs AB, Bobev S. The Zintl phases AIn 2As 2 (A = Ca, Sr, Ba): new topological insulators and thermoelectric material candidates. Dalton Trans 2021; 50:9173-9184. [PMID: 34121098 DOI: 10.1039/d1dt01521d] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Recently, there has been a lot of interest in topological insulators (TIs), being electronic materials, which are insulating in their bulk but with the gapless exotic metallic state on their surface. The surface states observed in such materials behave as a perfect conductor thereby making them more suited for several cutting-edge technological applications such as spintronic devices. Here, we report the synthesis and structural characterization of the Zintl phases AIn2As2 (A = Ca, Sr, Ba), which could become a new class of TIs. Crystal structure elucidation by single-crystal X-ray diffraction reveals that CaIn2As2 and SrIn2As2 are isostructural and crystallize in the EuIn2P2 structure type (space group P63/mmc, no. 194, Z = 2) with unit cell parameters a = 4.1482(6) Å, c = 17.726(4) Å; and a = 4.2222(6) Å, c = 18.110(3) Å, respectively. Their hexagonal structure is made up of alternating [In2As2]2- layers separated by slabs of A2+ cations. BaIn2As2 on the other hand crystallizes in the monoclinic EuGa2P2 structure type (space group P2/m, no. 10, Z = 4) with unit cell parameters a = 10.2746(11) Å, b = 4.3005(5) Å, c = 13.3317(14) Å and β = 95.569(2)°. This structure is also layered, and it is made up of different type of polyanionic [In2As2]2- units and Ba2+ cations. The valence electron count for all three compounds adheres to the Zintl-Klemm formalism, and all elements achieve closed-shell electronic configurations. Bulk electronic structure calculations indicate the opening of a bandgap Eg ∼ 0.03 eV (CaIn2As2 and Sr2In2As2), and Eg ∼0.21 eV (BaIn2As2) in the absence of strain and spin-orbit coupling (SOC). These results argue in favor of the realization of a nontrivial topological insulator state under the influence of tensile strain and SOC. Preliminary transport properties on BaIn2As2 are suggestive of a degenerate p-type semiconductor-a behavior which is sought after in thermoelectric (TE) materials. Since both TIs and excellent TE materials are known to favor the same material properties such as narrow bandgap, heavy elements, and strong SOC, these three Zintl phases are also projected as candidates TE materials.
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Affiliation(s)
- Michael O Ogunbunmi
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
| | - Sviatoslav Baranets
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
| | - Amanda B Childs
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
| | - Svilen Bobev
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
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Weippert V, Johrendt D. High-pressure synthesis and crystal structure of SrGa 4As 4. Acta Crystallogr E Crystallogr Commun 2019; 75:1643-1645. [PMID: 31709083 PMCID: PMC6829736 DOI: 10.1107/s2056989019013562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 10/04/2019] [Indexed: 06/10/2023]
Abstract
Strontium tetra-gallate(II,III) tetra-arsenide, SrGa4As4, was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 8 GPa and 1573 K. The com-pound crystallizes in a new structure type (P3221, Z = 3) as a three-dimensional (3D) framework of corner-sharing SrAs8 quadratic anti-prisms with strontium situated on a twofold rotation axis (Wyckoff position 3b). This arrangement is surrounded by a 3D framework which can be described as alternately stacked layers of either condensed GaIIIAs4 tetra-hedra or honeycomb-like layers built up from distorted ethane-like GaII 2As6 units com-prising Ga-Ga bonds.
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Affiliation(s)
- Valentin Weippert
- Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, D-81377 München, Germany
| | - Dirk Johrendt
- Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, D-81377 München, Germany
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Five new ternary indium-arsenides discovered. Synthesis and structural characterization of the Zintl phases Sr3In2As4, Ba3In2As4, Eu3In2As4, Sr5In2As6 and Eu5In2As6. J SOLID STATE CHEM 2019. [DOI: 10.1016/j.jssc.2019.07.050] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Weippert V, Haffner A, Stamatopoulos A, Johrendt D. Supertetrahedral Layers Based on GaAs or InAs. J Am Chem Soc 2019; 141:11245-11252. [DOI: 10.1021/jacs.9b04712] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Valentin Weippert
- Department of Chemistry, University of Munich (LMU), Butenandtstraße 5-13, 81377 Munich, Germany
| | - Arthur Haffner
- Department of Chemistry, University of Munich (LMU), Butenandtstraße 5-13, 81377 Munich, Germany
| | - Alexis Stamatopoulos
- Department of Chemistry, University of Munich (LMU), Butenandtstraße 5-13, 81377 Munich, Germany
| | - Dirk Johrendt
- Department of Chemistry, University of Munich (LMU), Butenandtstraße 5-13, 81377 Munich, Germany
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Ovchinnikov A, Bobev S. Layered Quaternary Germanides—Synthesis and Crystal and Electronic Structures of AELi2In2Ge2 (AE = Sr, Ba, Eu). Inorg Chem 2019; 58:7895-7904. [DOI: 10.1021/acs.inorgchem.9b00588] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander Ovchinnikov
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
- Department of Materials and Environmental Chemistry, Stockholm University, Svante Arrhenius väg 16 C, 10691 Stockholm, Sweden
| | - Svilen Bobev
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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New insights into the application of the valence rules in Zintl phases—Crystal and electronic structures of Ba7Ga4P9, Ba7Ga4As9, Ba7Al4Sb9, Ba6CaAl4Sb9, and Ba6CaGa4Sb9. J SOLID STATE CHEM 2016. [DOI: 10.1016/j.jssc.2015.07.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Synthesis, Crystal and Electronic Structures of the Pnictides AE3TrPn3 (AE = Sr, Ba; Tr = Al, Ga; Pn = P, As). CRYSTALS 2015. [DOI: 10.3390/cryst5040433] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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He H, Tyson C, Saito M, Bobev S. Synthesis, Crystal and Electronic Structures of the New Zintl phases Ba3Al3Pn5 (Pn = P, As) and Ba3Ga3P5. Inorg Chem 2012; 52:499-505. [DOI: 10.1021/ic302437t] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hua He
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United
States
| | - Chauntae Tyson
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United
States
| | - Maia Saito
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United
States
| | - Svilen Bobev
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United
States
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Synthesis and structural characterization of the ternary Zintl phases AE3Al2Pn4 and AE3Ga2Pn4 (AE=Ca, Sr, Ba, Eu; Pn=P, As). J SOLID STATE CHEM 2012. [DOI: 10.1016/j.jssc.2012.01.042] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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He H, Tyson C, Bobev S. Eight-Coordinated Arsenic in the Zintl Phases RbCd4As3 and RbZn4As3: Synthesis and Structural Characterization. Inorg Chem 2011; 50:8375-83. [DOI: 10.1021/ic2009418] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hua He
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Chauntae Tyson
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Svilen Bobev
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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Schellenberg I, Eul M, Pöttgen R. EuGa2Sb2: a new Zintl phase with four-bonded gallium and three-bonded antimony in a complex three-dimensional [Ga2Sb2] polyanion. MONATSHEFTE FUR CHEMIE 2011. [DOI: 10.1007/s00706-011-0544-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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