1
|
Bolotina NB, Dudka AP, Khrykina ON, Krasnorussky VN, Shitsevalova NY, Filipov VB, Sluchanko NE. The lower symmetry electron-density distribution and the charge transport anisotropy in cubic dodecaboride LuB 12. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:265402. [PMID: 29790852 DOI: 10.1088/1361-648x/aac742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
High-quality single crystals of LuB12 are grown using the induction zone melting method. The x-ray data are collected at temperatures 293, 135, 95, 50 K. The crystal structure of LuB12 can be refined with record low R-factor in the cubic Fm [Formula: see text] m symmetry group despite reiterated observations of the cubic symmetry distortions both in the unit-cell values and in the physical properties. A peculiar computing strategy is developed to resolve this contradiction. True symmetry of the electron-density distribution in LuB12 is proved to be much lower than cubic as a result, which correlates very accurately with anisotropy of transport properties of LuB12.
Collapse
Affiliation(s)
- Nadezhda B Bolotina
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre 'Crystallography and Photonics' of Russian Academy of Sciences, 59 Leninskii Ave., 119333 Moscow, Russia
| | | | | | | | | | | | | |
Collapse
|
2
|
Sartinska L, Chkhartishvili L, Voynich E, Eren T, Frolov G, Altay E, Murusidze I, Tsagareishvili O, Gabunia D, Maisuradze N. Effect of concentrated light on morphology and vibrational properties of boron and tantalum mixtures. Heliyon 2018; 4:e00585. [PMID: 29862348 PMCID: PMC5968138 DOI: 10.1016/j.heliyon.2018.e00585] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/28/2017] [Accepted: 03/19/2018] [Indexed: 11/03/2022] Open
Abstract
Heating a mixture of boron (impurities: carbon ∼ B50C2, boric acid - H3BO3) and tantalum (Ta) powders in nitrogen flow in a xenon high-flux optical furnace was performed. As-received powder composed of h-BN, H3BO3, TaB2, B9H11 and a number of other phases including β-rhombohedral boron, apparently, heavily doped with Ta. FT-IR examination of any sample of the material reveals the complicated vibration spectrum containing, in particular, an absorption band near 2260 cm-1. The shapes of these bands are different for samples because powders were synthesized at different temperatures. Known, that in β-rhombohedral boron lattice, there are nano-sized voids of different types, which allow an accommodation of single atoms or small groups of atoms. Theoretical calculations performed by the method of quasi-classical type yields the same value, 2260 cm-1, for the vibrations frequency of Ta atoms in D-type crystallographic voids in β-rhombohedral boron lattice. Since, Ta atoms are known to prefer accommodation just in D-voids the experimentally detected bands can be identified with localized vibrations of Ta atoms.
Collapse
Affiliation(s)
- Lina Sartinska
- Department of High-Temperature Processes & Tests of Materials for Rocket-Space Equipment, I. M. Frantsevich Institute for Problems of Materials Science of NASU, 3 Krzhyzhanovsky Str., Kyiv, 03680, Ukraine
| | - Levan Chkhartishvili
- Department of Engineering Physics, Georgian Technical University, 77 Kostava Ave., Tbilisi, 0175, Georgia.,Laboratory for Boron-Containing & Composite Materials, F. Tavadze Institute of Metallurgy & Materials Science, 10 Mindeli Str., Tbilisi, 0186, Georgia
| | - Eugen Voynich
- Department of High-Temperature Processes & Tests of Materials for Rocket-Space Equipment, I. M. Frantsevich Institute for Problems of Materials Science of NASU, 3 Krzhyzhanovsky Str., Kyiv, 03680, Ukraine
| | - Tarik Eren
- Chemistry Department, Faculty of Art & Sciences, Yildiz Technical University, Davutpasa Campus, Istanbul, 34220, Esenler, Turkey
| | - Gennadiy Frolov
- Department of High-Temperature Processes & Tests of Materials for Rocket-Space Equipment, I. M. Frantsevich Institute for Problems of Materials Science of NASU, 3 Krzhyzhanovsky Str., Kyiv, 03680, Ukraine
| | - Esra Altay
- Chemistry Department, Faculty of Art & Sciences, Yildiz Technical University, Davutpasa Campus, Istanbul, 34220, Esenler, Turkey
| | - Ivane Murusidze
- Institute of Applied Physics, Ilia State University, 3/5 Cholokashvili Ave., Tbilisi, 0162, Georgia
| | - Otar Tsagareishvili
- Laboratory for Boron-Containing & Composite Materials, F. Tavadze Institute of Metallurgy & Materials Science, 10 Mindeli Str., Tbilisi, 0186, Georgia
| | - Domenti Gabunia
- Laboratory for Boron-Containing & Composite Materials, F. Tavadze Institute of Metallurgy & Materials Science, 10 Mindeli Str., Tbilisi, 0186, Georgia
| | - Nodar Maisuradze
- Department of Engineering Physics, Georgian Technical University, 77 Kostava Ave., Tbilisi, 0175, Georgia
| |
Collapse
|
3
|
Bolotina NB, Verin IA, Shitsevalova NY, Filippov VB, Sluchanko NE. Structural features of single crystals of LuB12 upon a transition to the cage-glass phase. CRYSTALLOGR REP+ 2016. [DOI: 10.1134/s106377451602005x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
4
|
Werheit H, Filipov V, Shirai K, Dekura H, Shitsevalova N, Schwarz U, Armbrüster M. Raman scattering and isotopic phonon effects in dodecaborides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:065403. [PMID: 21406928 DOI: 10.1088/0953-8984/23/6/065403] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The Raman spectra of numerous dodecaborides have been measured on high-quality single crystals at ambient conditions with high spectral resolution and signal-to-noise ratio. Besides the strong Raman-active modes, numerous Raman-inactive modes occur in the spectra, indicating distortions of the structures. Ab initio calculation of the phonon spectra on ZrB(12) excellently agrees with the experimental results. Force constants are theoretically calculated and force parameters are estimated from the Raman frequencies. The influence of the surface range on the Raman spectra is evident. The different isotopic effects (virtual crystal approximation, the polarization effect and the effect of isotopic disorder) on the phonon frequencies are determined, separated and discussed.
Collapse
Affiliation(s)
- H Werheit
- Institute of Physics, University Duisburg-Essen, Campus Duisburg, D-47048 Duisburg, Germany.
| | | | | | | | | | | | | |
Collapse
|
5
|
Werheit H, Filipov V, Kuhlmann U, Schwarz U, Armbrüster M, Leithe-Jasper A, Tanaka T, Higashi I, Lundström T, Gurin VN, Korsukova MM. Raman effect in icosahedral boron-rich solids. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2010; 11:023001. [PMID: 27877328 PMCID: PMC5090270 DOI: 10.1088/1468-6996/11/2/023001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 06/01/2010] [Accepted: 03/30/2010] [Indexed: 05/13/2023]
Abstract
We present Raman spectra of numerous icosahedral boron-rich solids having the structure of α-rhombohedral, β-rhombohedral, α-tetragonal, β-tetragonal, YB66, orthorhombic or amorphous boron. The spectra were newly measured and, in some cases, compared with reported data and discussed. We emphasize the importance of a high signal-to-noise ratio in the Raman spectra for detecting weak effects evoked by the modification of compounds, accommodation of interstitial atoms and other structural defects. Vibrations of the icosahedra, occurring in all the spectra, are interpreted using the description of modes in α-rhombohedral boron by Beckel et al. The Raman spectrum of boron carbide is largely clarified. Relative intra- and inter-icosahedral bonding forces are estimated for the different structural groups and for vanadium-doped β-rhombohedral boron. The validity of Badger's rule is demonstrated for the force constants of inter-icosahedral B-B bonds, whereas the agreement is less satisfactory for the intra-icosahedral B-B bonds.
Collapse
Affiliation(s)
| | - Volodymyr Filipov
- I.N. Frantsevich Institute for Problems of Materials Science of NASU, 03142 Kiev, Ukraine
| | - Udo Kuhlmann
- Institute of Physics, University Duisburg-Essen, D-47048 Duisburg, Germany
- Present address: Pirelli Deutschland GmbH, D-64747 Breuberg
| | - Ulrich Schwarz
- Max-Plank-Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
| | - Marc Armbrüster
- Max-Plank-Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
| | | | - Takaho Tanaka
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Iwami Higashi
- Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-01, Japan
| | | | - Vladimir N Gurin
- Ioffe Physical–Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Maria M Korsukova
- Ioffe Physical–Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| |
Collapse
|
6
|
Werheit H, Filipov V, Schwarz U, Armbrüster M, Leithe-Jasper A, Tanaka T, Shalamberidze SO. On surface Raman scattering and luminescence radiation in boron carbide. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:045401. [PMID: 21386312 DOI: 10.1088/0953-8984/22/4/045401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The discrepancy between Raman spectra of boron carbide obtained by Fourier transform Raman and conventional Raman spectrometry is systematically investigated. While at photon energies below the exciton energy (1.560 eV), Raman scattering of bulk phonons of boron carbide occurs, photon energies exceeding the fundamental absorption edge (2.09 eV) evoke additional patterns, which may essentially be attributed to luminescence or to the excitation of Raman-active processes in the surface region. The reason for this is the very high fundamental absorption in boron carbide inducing a very small penetration depth of the exciting laser radiation. Raman excitations essentially restricted to the boron carbide surface region yield spectra which considerably differ from bulk phonon ones, thus indicating structural modifications.
Collapse
Affiliation(s)
- H Werheit
- Institute of Physics, University Duisburg-Essen, Duisburg, Germany.
| | | | | | | | | | | | | |
Collapse
|