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Mitchell TB, Zhang X, Jerozal RT, Chen YS, Wang S, Benedict JB. Development of a scalar-based geometric parameterization approach for the crystal structure landscape of dithienylethene-based crystalline solids. IUCrJ 2023; 10:694-699. [PMID: 37750828 PMCID: PMC10619447 DOI: 10.1107/s2052252523008060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 09/14/2023] [Indexed: 09/27/2023]
Abstract
Dithienylethenes (DTEs) are a promising class of organic photoswitches that can be used to create crystalline solids with properties controlled by light. However, the ability of DTEs to adopt multiple conformations, only one of which is photoactive, complicates the rational design of these materials. Herein, the synthesis and structural characterization of 19 crystalline solids containing a single DTE molecule are described. A novel D-D analysis of the molecular geometries obtained from rotational potential energy surface calculations and the ensemble of experimental structures were used to construct a crystal landscape for DTE. Of the 19 crystal structures, 17 contained photoinactive DTE rotamers and only 2 were photoactive. These results highlight the challenges associated with the design of these materials. Overall, the D-D analysis described herein provides rapid, effective and intuitive means of linking the molecular structure to photoactivity that could be applied more broadly to afford a general strategy for producing photoactive diarylethene-based crystalline solids.
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Affiliation(s)
- Travis B. Mitchell
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA
| | - Xiaotong Zhang
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA
| | - Ronald T. Jerozal
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA
| | - Yu-Sheng Chen
- NSF’s ChemMatCARS, University of Chicago, Chicago, Lemont, IL 60439, USA
| | - SuYin Wang
- NSF’s ChemMatCARS, University of Chicago, Chicago, Lemont, IL 60439, USA
| | - Jason B. Benedict
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA
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2
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Fan Q, Wu J, Zhao Y, Song Y, Yun S. High-throughput calculation screening for new silicon allotropes with monoclinic symmetry. IUCrJ 2023; 10:S2052252523004207. [PMID: 37335767 DOI: 10.1107/s2052252523004207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 05/14/2023] [Indexed: 06/21/2023]
Abstract
A total of 87 new monoclinic silicon allotropes are systematically scanned by a random strategy combined with group and graph theory and high-throughput calculations. The new allotropes include 13 with a direct or quasi-direct band gap and 12 with metallic characteristics, and the rest are indirect band gap semiconductors. More than 30 of these novel monoclinic Si allotropes show bulk moduli greater than or equal to 80 GPa, and three of them show even greater bulk moduli than diamond Si. Only two of the new Si allotropes show a greater shear modulus than diamond Si. The crystal structures, stability (elastic constants, phonon spectra), mechanical properties, electronic properties, effective carrier masses and optical properties of all 87 Si monoclinic allotropes are studied in detail. The electron effective masses ml of five of the new allotropes are smaller than that of diamond Si. All of these novel monoclinic Si allotropes show strong absorption in the visible spectral region. Taken together with their electronic band gap structures, this makes them promising materials for photovoltaic applications. These investigations greatly enrich the current knowledge of the structure and electronic properties of silicon allotropes.
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Affiliation(s)
- Qingyang Fan
- College of Information and Control Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province 710055, People's Republic of China
| | - Jie Wu
- College of Science, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province 710055, People's Republic of China
| | - Yingbo Zhao
- School of Mechanical and Electrical Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province 710055, People's Republic of China
| | - Yanxing Song
- School of Microelectronics, Xidian University, Xi'an, Shaanxi Province 710071, People's Republic of China
| | - Sining Yun
- School of Materials Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province 710055, People's Republic of China
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3
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Shan P, Long X. Symmetry of antiferroelectric crystals crystallized in polar point groups. IUCrJ 2022; 9:516-522. [PMID: 35844473 PMCID: PMC9252155 DOI: 10.1107/s2052252522006017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Symmetry is an essential concept in physics, chemistry and materials science. Comprehensive, authoritative and accessible symmetry theory can provide a strong impetus for the development of related materials science. Through the sustained efforts of physicists and crystallographers, researchers have mastered the relationship between structural symmetry and ferroelectricity, which demands crystallization in the 10 polar point groups. However, the symmetry requirement for antiferroelectricity is still ambiguous, and polar crystals possessing antiferroelectricity seem contradictory. This work systematically and comprehensively studies the transformation of dipole moments under symmetry operations, using accessible geometric methods and group theory. The results indicate crystals that crystallize in polar point groups 2 (C 2), m (C 1h), mm2 (C 2v), 4 (C 4), 4mm (C 4v), 3m (C 3v), 6 (C 6) and 6mm (C 6v) also possess anti-polar structure and are capable of Kittel-type antiferroelectricity. The anti-polar direction of each point group is also highlighted, which could provide a straightforward guide for antiferroelectric property measurement. Like ferroelectric crystals, antiferroelectric crystals belonging to polar point groups have great potential to become a family of important multifunctional electroactive and optical materials. This contribution refines antiferroelectric theory, will help facilitate and stimulate the discovery and rational design of novel antiferroelectric crystals, and enrich the potential functional applications of antiferroelectric materials.
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Affiliation(s)
- Pai Shan
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People’s Republic of China
| | - Xifa Long
- Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People’s Republic of China
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4
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Ding X, Zahid E, Unruh DK, Hutchins KM. Differences in thermal expansion and motion ability for herringbone and face-to-face π-stacked solids. IUCrJ 2022; 9:31-42. [PMID: 35059207 PMCID: PMC8733877 DOI: 10.1107/s2052252521009593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/15/2021] [Indexed: 06/14/2023]
Abstract
A series of aromatic organic molecules functionalized with different halogen atoms (I/ Br), motion-capable groups (olefin, azo or imine) and molecular length were designed and synthesized. The molecules self-assemble in the solid state through halogen bonding and exhibit molecular packing sustained by either herringbone or face-to-face π-stacking, two common motifs in organic semiconductor molecules. Interestingly, dynamic pedal motion is only achieved in solids with herringbone packing. On average, solids with herringbone packing exhibit larger thermal expansion within the halogen-bonded sheets due to motion occurrence and molecular twisting, whereas molecules with face-to-face π-stacking do not undergo motion or twisting. Thermal expansion along the π-stacked direction is surprisingly similar, but slightly larger for the face-to-face π-stacked solids due to larger changes in π-stacking distances with temperature changes. The results speak to the importance of crystal packing and intermolecular interaction strength when designing aromatic-based solids for organic electronics applications.
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Affiliation(s)
- Xiaodan Ding
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Ethan Zahid
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Daniel K. Unruh
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - Kristin M. Hutchins
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
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5
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Tchoń D, Makal A. Maximizing completeness in single-crystal high-pressure diffraction experiments: phase transitions in 2°AP. IUCrJ 2021; 8:1006-1017. [PMID: 34804552 PMCID: PMC8562673 DOI: 10.1107/s2052252521009532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Sufficiently high completeness of diffraction data is necessary to correctly determine the space group, observe solid-state structural transformations or investigate charge density distribution under pressure. Regrettably, experiments performed at high pressure in a diamond anvil cell (DAC) yield inherently incomplete datasets. The present work systematizes the combined influence of radiation wavelength, DAC opening angle and sample orientation in a DAC on the completeness of diffraction data collected in a single-crystal high-pressure (HP) experiment with the help of dedicated software. In particular, the impact of the sample orientation on the achievable data completeness is quantified and proved to be substantial. Graphical guides for estimating the most beneficial sample orientation depending on the sample Laue class and assuming a few commonly used experimental setups are proposed. The usefulness of these guides has been tested in the case of luminescent 1,3-diacetylpyrene, suspected to undergo transitions from the α phase (Pnma) to the γ phase (Pn21 a) and δ phase (P1121/a) under pressure. Effective sample orientation has ensured over 90% coverage even for the monoclinic system and enabled unrestrained structure refinements and access to complete systematic extinction patterns.
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Affiliation(s)
- D. Tchoń
- Biological and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warszawa, Poland
| | - A. Makal
- Biological and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warszawa, Poland
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Roth N, Zhu T, Iversen BB. A simple model for vacancy order and disorder in defective half-Heusler systems. IUCrJ 2020; 7:673-680. [PMID: 32695414 PMCID: PMC7340261 DOI: 10.1107/s2052252520005977] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
Defective half-Heusler systems X 1-x YZ with large amounts of intrinsic vacancies, such as Nb1-x CoSb, Ti1-x NiSb and V1-x CoSb, are a group of promising thermoelectric materials. Even with high vacancy concentrations they maintain the average half-Heusler crystal structure. These systems show high electrical conductivity but low thermal conductivity arising from an ordered YZ substructure, which conducts electrons, while the large amounts of vacancies in the X substructure effectively scatters phonons. Using electron scattering, it was recently observed that, in addition to Bragg diffraction from the average cubic half-Heusler structure, some of these samples show broad diffuse scattering indicating short-range vacancy order, while other samples show sharp additional peaks indicating long-range vacancy ordering. Here it is shown that both the short- and long-range ordering can be explained using the same simple model, which assumes that vacancies in the X substructure avoid each other. The samples showing long-range vacancy order are in agreement with the predicted ground state of the model, while short-range order samples are quenched high-temperature states of the system. A previous study showed that changes in sample stoichiometry affect whether the short- or long-range vacancy structure is obtained, but the present model suggests that thermal treatment of samples should allow controlling the degree of vacancy order, and thereby the thermal conductivity, without changes in composition. This is important as the composition also dictates the amount of electrical carriers. Independent control of electrical carrier concentration and degree of vacancy order should allow further improvements in the thermoelectric properties of these systems.
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Affiliation(s)
- Nikolaj Roth
- Center for Materials Crystallography, Department of Chemistry, Aarhus University, Aarhus 8000, Denmark
| | - Tiejun Zhu
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People’s Republic of China
| | - Bo B. Iversen
- Center for Materials Crystallography, Department of Chemistry, Aarhus University, Aarhus 8000, Denmark
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Yadava K, Gallo G, Bette S, Mulijanto CE, Karothu DP, Park IH, Medishetty R, Naumov P, Dinnebier RE, Vittal JJ. Extraordinary anisotropic thermal expansion in photosalient crystals. IUCrJ 2020; 7:83-89. [PMID: 31949907 PMCID: PMC6949593 DOI: 10.1107/s2052252519014581] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 10/27/2019] [Indexed: 06/01/2023]
Abstract
Although a plethora of metal complexes have been characterized, those having multifunctional properties are very rare. This article reports three isotypical complexes, namely [Cu(benzoate)L 2], where L = 4-styryl-pyridine (4spy) (1), 2'-fluoro-4-styryl-pyridine (2F-4spy) (2) and 3'-fluoro-4-styryl-pyridine (3F-4spy) (3), which show photosalient behavior (photoinduced crystal mobility) while they undergo [2+2] cyclo-addition. These crystals also exhibit anisotropic thermal expansion when heated from room temperature to 200°C. The overall thermal expansion of the crystals is impressive, with the largest volumetric thermal expansion coefficients for 1, 2 and 3 of 241.8, 233.1 and 285.7 × 10-6 K-1, respectively, values that are comparable to only a handful of other reported materials known to undergo colossal thermal expansion. As a result of the expansion, their single crystals occasionally move by rolling. Altogether, these materials exhibit unusual and hitherto untapped solid-state properties.
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Affiliation(s)
- Khushboo Yadava
- Department of Chemistry, National University of Singapore, S8-05-03, 3 Science Drive 3, 117543, Singapore
| | - Gianpiero Gallo
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D70569 Stuttgart Germany
- Department of Chemistry and Biology ‘A. Zambelli’, University of Salerno, Via Giovanni Paolo II, 132, Fisciano (SA) 84084, Italy
| | - Sebastian Bette
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D70569 Stuttgart Germany
| | - Caroline Evania Mulijanto
- Department of Chemistry, National University of Singapore, S8-05-03, 3 Science Drive 3, 117543, Singapore
| | | | - In-Hyeok Park
- Department of Chemistry, National University of Singapore, S8-05-03, 3 Science Drive 3, 117543, Singapore
| | - Raghavender Medishetty
- Department of Chemistry, National University of Singapore, S8-05-03, 3 Science Drive 3, 117543, Singapore
| | - Panče Naumov
- New York University Abu Dhabi, 129188, Abu Dhabi, United Arab Emirates
| | - Robert E. Dinnebier
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D70569 Stuttgart Germany
| | - Jagadese J. Vittal
- Department of Chemistry, National University of Singapore, S8-05-03, 3 Science Drive 3, 117543, Singapore
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Voufack AB, Kibalin I, Yan Z, Claiser N, Gueddida S, Gillon B, Porcher F, Gukasov A, Sugimoto K, Lecomte C, Dahaoui S, Gillet JM, Souhassou M. Spin resolved electron density study of YTiO 3 in its ferromagnetic phase: signature of orbital ordering. IUCrJ 2019; 6:884-894. [PMID: 31576221 PMCID: PMC6760435 DOI: 10.1107/s2052252519009230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/27/2019] [Indexed: 06/10/2023]
Abstract
The present work reports on the charge and spin density modelling of YTiO3 in its ferromagnetic state (T C = 27 K). Accurate polarized neutron diffraction and high-resolution X-ray diffraction (XRD) experiments were carried out on a single crystal at the ORPHÉE reactor (LLB) and SPRING8 synchrotron source. The experimental data are modelled by the spin resolved pseudo-atomic multipolar model (Deutsch et al., 2012 ▸). The refinement strategy is discussed and the result of this electron density modelling is compared with that from XRD measured at 100 K and with density functional theory calculations. The results show that the spin and charge densities around the Ti atom have lobes directed away from the O atoms, confirming the filling of the t 2g orbitals of the Ti atom. The d xy orbital is less populated than d xz and d yz , which is a sign of a partial lift of degeneracy of the t 2g orbitals. This study confirms the orbital ordering at low temperature (20 K), which is already present in the paramagnetic state above the ferromagnetic transition (100 K).
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Affiliation(s)
- Ariste Bolivard Voufack
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- CNRS, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Iurii Kibalin
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- PNPI NRC, Kurcharov Institut, Orlova Rosha, Gatchina, Leningrad region 188300, Russian Federation
| | - Zeyin Yan
- CentraleSupelec, Grande Voie des Vignes, 92295 Chatenay-Malabry Cedex, France
| | - Nicolas Claiser
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- CNRS, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Saber Gueddida
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Béatrice Gillon
- LLB, CEA-CNRS, UMR 12, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Florence Porcher
- LLB, CEA-CNRS, UMR 12, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Arsen Gukasov
- LLB, CEA-CNRS, UMR 12, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Kunishisa Sugimoto
- SPring-8, Japan Synchrtron Radiation Research Institut, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
| | - Claude Lecomte
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- CNRS, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Slimane Dahaoui
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
| | - Jean-Michel Gillet
- SPMS, UMR 8580, CentraleSupelec, Paris Saclay University, 91191 Gif-sur-Yvette, France
| | - Mohamed Souhassou
- Université de Lorraine, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
- CNRS, Laboratoire CRM2, UMR CNRS 7036, Boulevard des aiguillettes BP70239, 54506 Vandoeure-les-Nancy, France
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Belo EA, Pereira JEM, Freire PTC, Argyriou DN, Eckert J, Bordallo HN. Hydrogen bonds in crystalline d-alanine: diffraction and spectroscopic evidence for differences between enantiomers. IUCrJ 2018; 5:6-12. [PMID: 29354266 PMCID: PMC5755572 DOI: 10.1107/s2052252517015573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 10/25/2017] [Indexed: 06/07/2023]
Abstract
Enantiomeric amino acids have specific physiological functions in complex biological systems. Systematic studies focusing on the solid-state properties of d-amino acids are, however, still limited. To shed light on this field, structural and spectroscopic studies of d-alanine using neutron powder diffraction, polarized Raman scattering and ab initio calculations of harmonic vibrational frequencies were carried out. Clear changes in the number of vibrational modes are observed as a function of temperature, which can be directly connected to variations of the N-D bond lengths. These results reveal dissimilarities in the structural properties of d-alanine compared with l-alanine.
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Affiliation(s)
- Ezequiel A. Belo
- Faculdade de Física, Universidade Federal do Pará, Belém, Pará, Brazil
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - Jose E. M. Pereira
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, Copenhagen, 2100, Denmark
| | - Paulo T. C. Freire
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | | | - Juergen Eckert
- Department of Chemistry, University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620, USA
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Heloisa N. Bordallo
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, Copenhagen, 2100, Denmark
- Department of Chemistry, University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620, USA
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Kim H, Meng Y, Kwon JH, Rouviére JL, Zuo JM. Determination of atomic vacancies in InAs/GaSb strained-layer superlattices by atomic strain. IUCrJ 2018; 5:67-72. [PMID: 29354272 PMCID: PMC5755578 DOI: 10.1107/s2052252517016219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 11/09/2017] [Indexed: 06/07/2023]
Abstract
Determining vacancy in complex crystals or nanostructures represents an outstanding crystallographic problem that has a large impact on technology, especially for semiconductors, where vacancies introduce defect levels and modify the electronic structure. However, vacancy is hard to locate and its structure is difficult to probe experimentally. Reported here are atomic vacancies in the InAs/GaSb strained-layer superlattice (SLS) determined by atomic-resolution strain mapping at picometre precision. It is shown that cation and anion vacancies in the InAs/GaSb SLS give rise to local lattice relaxations, especially the nearest atoms, which can be detected using a statistical method and confirmed by simulation. The ability to map vacancy defect-induced strain and identify its location represents significant progress in the study of vacancy defects in compound semiconductors.
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Affiliation(s)
- Honggyu Kim
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA
| | - Yifei Meng
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA
| | - Ji-Hwan Kwon
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA
| | | | - Jian Min Zuo
- Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA
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11
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Matvienko AA, Maslennikov DV, Zakharov BA, Sidelnikov AA, Chizhik SA, Boldyreva EV. Structural aspects of displacive transformations: what can optical microscopy contribute? Dehydration of Sm 2(C 2O 4) 3·10H 2O as a case study. IUCrJ 2017; 4:588-597. [PMID: 28932405 PMCID: PMC5600022 DOI: 10.1107/s2052252517008624] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 06/09/2017] [Indexed: 06/07/2023]
Abstract
For martensitic transformations the macroscopic crystal strain is directly related to the corresponding structural rearrangement at the microscopic level. In situ optical microscopy observations of the interface migration and the change in crystal shape during a displacive single crystal to single crystal transformation can contribute significantly to understanding the mechanism of the process at the atomic scale. This is illustrated for the dehydration of samarium oxalate decahydrate in a study combining optical microscopy and single-crystal X-ray diffraction.
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Affiliation(s)
- Alexander A. Matvienko
- Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Kutateladze Street 18, Novosibirsk 630128, Russian Federation
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation
| | - Daniel V. Maslennikov
- Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Kutateladze Street 18, Novosibirsk 630128, Russian Federation
| | - Boris A. Zakharov
- Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Kutateladze Street 18, Novosibirsk 630128, Russian Federation
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation
| | - Anatoly A. Sidelnikov
- Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Kutateladze Street 18, Novosibirsk 630128, Russian Federation
| | - Stanislav A. Chizhik
- Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Kutateladze Street 18, Novosibirsk 630128, Russian Federation
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation
| | - Elena V. Boldyreva
- Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Kutateladze Street 18, Novosibirsk 630128, Russian Federation
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12
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Eikeland E, Blichfeld AB, Borup KA, Zhao K, Overgaard J, Shi X, Chen L, Iversen BB. Crystal structure across the β to α phase transition in thermoelectric Cu 2-x Se. IUCrJ 2017; 4:476-485. [PMID: 28875034 PMCID: PMC5571810 DOI: 10.1107/s2052252517005553] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 04/12/2017] [Indexed: 05/21/2023]
Abstract
The crystal structure uniquely imparts the specific properties of a material, and thus provides the starting point for any quantitative understanding of thermoelectric properties. Cu2-x Se is an intensely studied high performing, non-toxic and cheap thermoelectric material, and here for the first time, the average structure of β-Cu2-x Se is reported based on analysis of multi-temperature single-crystal X-ray diffraction data. It consists of Se-Cu layers with additional copper between every alternate layer. The structural changes during the peculiar zT enhancing phase transition mainly consist of changes in the inter-layer distance coupled with subtle Cu migration. Just prior to the transition the structure exhibits strong negative thermal expansion due to the reordering of Cu atoms, when approached from low temperatures. The phase transition is fully reversible and group-subgroup symmetry relations are derived that relate the low-temperature β-phase to the high-temperature α-phase. Weak superstructure reflections are observed and a possible Cu ordering is proposed. The structural rearrangement may have a significant impact on the band structure and the Cu rearrangement may also be linked to an entropy increase. Both factors potentially contribute to the extraordinary zT enhancement across the phase transition.
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Affiliation(s)
- Espen Eikeland
- Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Langelandsgade 140, Aarhus 8000-DK, Denmark
| | - Anders B. Blichfeld
- Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Langelandsgade 140, Aarhus 8000-DK, Denmark
| | - Kasper A. Borup
- Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Langelandsgade 140, Aarhus 8000-DK, Denmark
- National Renewable Energy Laboratory, 15013 Denver W Pkwy, Golden, CO 80401, USA
| | - Kunpeng Zhao
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, People’s Republic of China
| | - Jacob Overgaard
- Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Langelandsgade 140, Aarhus 8000-DK, Denmark
| | - Xun Shi
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, People’s Republic of China
| | - Lidong Chen
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, People’s Republic of China
| | - Bo B. Iversen
- Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Langelandsgade 140, Aarhus 8000-DK, Denmark
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Park WB, Chung J, Jung J, Sohn K, Singh SP, Pyo M, Shin N, Sohn KS. Classification of crystal structure using a convolutional neural network. IUCrJ 2017; 4:486-494. [PMID: 28875035 PMCID: PMC5571811 DOI: 10.1107/s205225251700714x] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/15/2017] [Indexed: 05/23/2023]
Abstract
A deep machine-learning technique based on a convolutional neural network (CNN) is introduced. It has been used for the classification of powder X-ray diffraction (XRD) patterns in terms of crystal system, extinction group and space group. About 150 000 powder XRD patterns were collected and used as input for the CNN with no handcrafted engineering involved, and thereby an appropriate CNN architecture was obtained that allowed determination of the crystal system, extinction group and space group. In sharp contrast with the traditional use of powder XRD pattern analysis, the CNN never treats powder XRD patterns as a deconvoluted and discrete peak position or as intensity data, but instead the XRD patterns are regarded as nothing but a pattern similar to a picture. The CNN interprets features that humans cannot recognize in a powder XRD pattern. As a result, accuracy levels of 81.14, 83.83 and 94.99% were achieved for the space-group, extinction-group and crystal-system classifications, respectively. The well trained CNN was then used for symmetry identification of unknown novel inorganic compounds.
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Affiliation(s)
- Woon Bae Park
- Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Republic of Korea
| | - Jiyong Chung
- Laboratory of Big-data Applications for Public Sector, Chung-Ang University, 221 Heukseok-dong, Dongjak-gu, Seoul 156-756, Republic of Korea
| | - Jaeyoung Jung
- Laboratory of Big-data Applications for Public Sector, Chung-Ang University, 221 Heukseok-dong, Dongjak-gu, Seoul 156-756, Republic of Korea
| | - Keemin Sohn
- Laboratory of Big-data Applications for Public Sector, Chung-Ang University, 221 Heukseok-dong, Dongjak-gu, Seoul 156-756, Republic of Korea
| | - Satendra Pal Singh
- Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Republic of Korea
| | - Myoungho Pyo
- Department of Printed Electronics Engineering, Sunchon National University, Chonnam 540-742 Republic of Korea
| | - Namsoo Shin
- Deep Solution Inc., 2636 Nambusunhwan-ro, Seocho-gu, Seoul 06738, Republic of Korea
| | - Kee-Sun Sohn
- Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Republic of Korea
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