| 1. |
- Verchenko, V. Yu, et al.
(author)
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Intermetallic solid solution Fe1-xCoxGa3 : Synthesis, structure, NQR study and electronic band structure calculations
- 2012
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In: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 194, s. 361-368
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Journal article (peer-reviewed)abstract
- Unlimited solid solution Fe1-xCoxGa3 was prepared from Ga flux. Its crystal structure was refined for Fe0.5Co0.5Ga3 (P4(2)/mnm, a=6.2436(9), c=6.4654(13), Z=4) and showed no ordering of the metal atoms. A combination of the electronic band structure calculations within the density functional theory (DFT) approach and Ga-69,Ga-71 nuclear quadrupole resonance (NRQ) spectroscopy clearly shows that the Fe-Fe and Co-Co dumbbells are preferred to the Fe-Co dumbbells in the crystals structure. The band structure features a band gap of about 0.4 eV, with the Fermi level crossing peaks of a substantial density of electronic states above the gap for x > 0. The solid solution is metallic for x > 0.025. The study of the nuclear spin-lattice relaxation shows that the rate of the relaxation, 1/T-1, is very sensitive to the Co concentration and correlates well with the square of the density of states at the Fermi level, N-2(E-F).
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| 2. |
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| 3. |
- Choubina, Tatiana, 1950-, et al.
(author)
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The slow light in GaN
- 2008
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In: ICPS2008,2008. ; , s. 647-
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Conference paper (peer-reviewed)
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| 4. |
- Dyakov, S. A., et al.
(author)
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Plasmon induced modification of silicon nanocrystals photoluminescence in presence of gold nanostripes
- 2018
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In: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
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Journal article (peer-reviewed)abstract
- We report on the results of theoretical and experimental studies of photoluminescense of silicon nanocrystals in the proximity to plasmonic modes of different types. In the studied samples, the type of plasmonic mode is determined by the filling ratio of a one-dimensional array of gold stripes which covers the thin film with silicon nanocrystals on a quartz substrate. We analyze the extinction, photoluminesce spectra and decay kinetics of silicon nanocrystals and show that the incident and emitted light is coupled to the corresponding plasmonic mode. We demonstrate the modification of the extinction and photoluminesce spectra under the transition from wide to narrow gold stripes. The experimental extinction and photoluminescense spectra are in good agreement with theoretical calculations performed by the rigorous coupled wave analysis. We study the contribution of individual silicon nanocrystals to the overall photoluminescense intensity, depending on their spacial position inside the structure.
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| 5. |
- Shubina, Tatiana, et al.
(author)
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Resonant light delay in GaN with ballistic and diffusive propagation
- 2008
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:8
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Journal article (peer-reviewed)abstract
- We report on a strong delay in light propagation through bulk GaN, detected by time-of-flight spectroscopy. The delay increases resonantly as the photon energy approaches the energy of a neutral-donor bound exciton (BX), resulting in a velocity of light as low as 2100 km/s. In the close vicinity of the BX resonance, the transmitted light contains both ballistic and diffusive components. This phenomenon is quantitatively explained in terms of optical dispersion in a medium where resonant light scattering by the BX resonance takes place in addition to the polariton propagation.
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| 6. |
- Choubina, Tatiana, 1950-, et al.
(author)
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Slow light in GaN
- 2008
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In: 16th Int. Symp. ¿Nanostructures: Physics and Technology,2008. ; , s. 257-
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Conference paper (peer-reviewed)
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| 7. |
- Dyakov, Sergey, et al.
(author)
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Optical properties of silicon nanocrystals covered by periodic array of gold nanowires
- 2016
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In: Physical Review B. - : American Physical Society. - 2469-9950. ; 93:20
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Journal article (peer-reviewed)abstract
- Extinction and photoluminescence spectra are experimentally and theoretically studied for a periodic array of gold nanowires deposited on top of a dielectric substrate containing silicon nanocrystals. Quasiguided modes are observed in the substrate resulting in modification of optical properties of silicon nanocrystals. Our calculations of extinction and photoluminescence spectra are in good agreement with experimental results. The periodicity provides a powerful tool for achieving a high photoluminescence outcoupling efficiency of silicon nanocrystals.
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| 8. |
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| 9. |
- Shubina, T.V., et al.
(author)
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Delay and distortion of light pulses by exciton resonancesin wide-gap semiconductors
- 2012
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In: Proceedings of the 20th Int. Symp. “Nanostructures: Physics and Technology". - 9785913261793 ; , s. 18-19
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Conference paper (peer-reviewed)abstract
- Propagation of light pulses in wide-gap semiconductors, GaN and ZnO, has been studied by time-of-flightspectroscopy. It has been demonstrated that significant light delay exists near an exciton resonance and that this delay isaccompanied by pulse distortion and attenuation. Simulation of the pulse shape in the time-energy plane has permitted us torefine excitonic parameters inherent for bulk materials. The time-of-flight studies done over a wide temperature rangedemonstrate the strong influence of resonant scattering by phonons on the light delay in polar semiconductors.
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| 10. |
- Shubina, T V, et al.
(author)
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Delay and distortion of slow light pulses by excitons in ZnO
- 2011
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In: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 84:7, s. 075202-
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Journal article (peer-reviewed)abstract
- istortion of light pulses in ZnO caused by both bound and free excitons is demonstrated by time-of-flight spectroscopy. Numerous lines of bound excitons dissect the pulse spectrum and induce slowdown of light propagation around the dips. Exciton-polariton resonances determine the overall pulse delay, which approaches 1.6 ns at 3.374 eV for a 0.3 mm propagation length, as well as the pulse curvature in the time-energy plane and its attenuation. Analysis of cw and time-resolved data yields the excitonic parameters inherent for bulk ZnO. A discrepancy is found between these bulk parameters and those given by surface-probing techniques.
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