First-principles calculations of yttrium tantalate and niobate crystals

The structural and electronic properties of yttrium tantalate (YTaO4) and yttrium niobate (YNbO4) crystals are studied using experimental and first-principles GGA U total energy calculations. The band gap of the host lattice from absorption and luminescence experiment is measured to be 5.1 eV for YT...

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Autores principales:	Nazarov, Mihail, Leng, L., Leong, Y., Chen, L., Arellano, I.
Formato:	article
Lenguaje:	EN
Publicado:	D.Ghitu Institute of Electronic Engineering and Nanotechnologies 2014
Materias:	Physics QC1-999 Electronics TK7800-8360
Acceso en línea:	https://doaj.org/article/49b6dd3237a048b08aef42497271226b
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spelling	oai:doaj.org-article:49b6dd3237a048b08aef42497271226b2021-11-21T11:59:30ZFirst-principles calculations of yttrium tantalate and niobate crystals539.1/.2+5442537-63651810-648Xhttps://doaj.org/article/49b6dd3237a048b08aef42497271226b2014-12-01T00:00:00Zhttps://mjps.nanotech.md/archive/2014/article/36734https://doaj.org/toc/1810-648Xhttps://doaj.org/toc/2537-6365The structural and electronic properties of yttrium tantalate (YTaO4) and yttrium niobate (YNbO4) crystals are studied using experimental and first-principles GGA U total energy calculations. The band gap of the host lattice from absorption and luminescence experiment is measured to be 5.1 eV for YTaO4 and 4.1eV for YNbO4. This is close to 5.14 eV and 4.28 eV, respectively, reproduced by means of GGA U approach. In our calculation, we tune both Hubbard energy U and exchange parameter J to reproduce the energy gap measured experimentally. It is found that Hubbard energy U plays a major role in reproducing the experimentally measured energy gap, but exchange parameter J does not. We also calculate the density of states (DOS) using the optimized U to interpret the experimentally measured luminescence spectra. Both the experimental and DOS calculations show that the valence band of tantalate (Ta) and niobate (Nb) systems is mainly composed of oxygen (O) 2p states. The lower conduction band is mainly composed of Ta 5d states or Nb 4d states, respectively, while the upper conduction band involves the contribution mainly from yttrium (Y) 4d states, with the middle conduction band mainly a mixture of Ta or Nb and Y states. The calculated partial DOS of each atom in the tantalate and niobate system is then compared with the UV and VUV spectra from photoluminescence excitation (PLE) experiment to explain the nature of the bands observed.Nazarov, MihailLeng, L.Leong, Y.Chen, L.Arellano, I.D.Ghitu Institute of Electronic Engineering and NanotechnologiesarticlePhysicsQC1-999ElectronicsTK7800-8360ENMoldavian Journal of the Physical Sciences, Vol 13, Iss 1-2, Pp 106-120 (2014)
institution	DOAJ
collection	DOAJ
language	EN
topic	Physics QC1-999 Electronics TK7800-8360
spellingShingle	Physics QC1-999 Electronics TK7800-8360 Nazarov, Mihail Leng, L. Leong, Y. Chen, L. Arellano, I. First-principles calculations of yttrium tantalate and niobate crystals
description	The structural and electronic properties of yttrium tantalate (YTaO4) and yttrium niobate (YNbO4) crystals are studied using experimental and first-principles GGA U total energy calculations. The band gap of the host lattice from absorption and luminescence experiment is measured to be 5.1 eV for YTaO4 and 4.1eV for YNbO4. This is close to 5.14 eV and 4.28 eV, respectively, reproduced by means of GGA U approach. In our calculation, we tune both Hubbard energy U and exchange parameter J to reproduce the energy gap measured experimentally. It is found that Hubbard energy U plays a major role in reproducing the experimentally measured energy gap, but exchange parameter J does not. We also calculate the density of states (DOS) using the optimized U to interpret the experimentally measured luminescence spectra. Both the experimental and DOS calculations show that the valence band of tantalate (Ta) and niobate (Nb) systems is mainly composed of oxygen (O) 2p states. The lower conduction band is mainly composed of Ta 5d states or Nb 4d states, respectively, while the upper conduction band involves the contribution mainly from yttrium (Y) 4d states, with the middle conduction band mainly a mixture of Ta or Nb and Y states. The calculated partial DOS of each atom in the tantalate and niobate system is then compared with the UV and VUV spectra from photoluminescence excitation (PLE) experiment to explain the nature of the bands observed.
format	article
author	Nazarov, Mihail Leng, L. Leong, Y. Chen, L. Arellano, I.
author_facet	Nazarov, Mihail Leng, L. Leong, Y. Chen, L. Arellano, I.
author_sort	Nazarov, Mihail
title	First-principles calculations of yttrium tantalate and niobate crystals
title_short	First-principles calculations of yttrium tantalate and niobate crystals
title_full	First-principles calculations of yttrium tantalate and niobate crystals
title_fullStr	First-principles calculations of yttrium tantalate and niobate crystals
title_full_unstemmed	First-principles calculations of yttrium tantalate and niobate crystals
title_sort	first-principles calculations of yttrium tantalate and niobate crystals
publisher	D.Ghitu Institute of Electronic Engineering and Nanotechnologies
publishDate	2014
url	https://doaj.org/article/49b6dd3237a048b08aef42497271226b
work_keys_str_mv	AT nazarovmihail firstprinciplescalculationsofyttriumtantalateandniobatecrystals AT lengl firstprinciplescalculationsofyttriumtantalateandniobatecrystals AT leongy firstprinciplescalculationsofyttriumtantalateandniobatecrystals AT chenl firstprinciplescalculationsofyttriumtantalateandniobatecrystals AT arellanoi firstprinciplescalculationsofyttriumtantalateandniobatecrystals
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First-principles calculations of yttrium tantalate and niobate crystals

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