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BiFeO_3陶瓷的光学性质的第一性原理研究（英文）.docx

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BiFeO_3陶瓷的光学性质的第一性原理研究（英文） First-principlesstudyoftheopticalpropertiesofBiFeO3ceramics Introduction: Bismuthferrite(BiFeO3)isamultiferroicmaterialthatexhibitsbothferroelectricityandantiferromagnetism.Duetoitsuniqueproperties,BiFeO3hasattractedextensiveresearchattentioninvariousfieldssuchasdatastorage,catalysis,piezoelectricity,andoptoelectronics.TheopticalpropertiesofBiFeO3ceramicsareofgreatinterestforphotovoltaicandphotocatalysisapplications.Inthisstudy,weinvestigatetheopticalpropertiesofBiFeO3ceramicsusingfirst-principlescalculations. Methods: Thecalculationsareperformedusingthedensityfunctionaltheory(DFT)withinthegeneralizedgradientapproximation(GGA)withthePerdew-Burke-Ernzerhof(PBE)exchange-correlationfunctionals.Theprojectoraugmentedwave(PAW)methodisusedtodescribetheelectron-ioninteraction.TheBrillouinzoneintegrationiscarriedoutusingtheMonkhorst-Packmethodwithak-pointmeshof6x6x6.Theopticalpropertiesaredeterminedusingtheimaginarypartofthedielectricfunction. Results: ThecalculatedbandstructureofBiFeO3showsabandgapof2.8eV,whichisingoodagreementwithexperimentalmeasurements.TheopticalspectraofBiFeO3ceramicsarecalculatedintheenergyrangeof0-8eV.Therealpartofthedielectricfunctionshowsasharppeakat3.0eV,whichcorrespondstothebandgapofBiFeO3.Theimaginarypartofthedielectricfunctionexhibitsabroadabsorptionpeakintheenergyrangeof2.5-5.0eV,whichisattributedtotheexcitonictransitionsbetweenthevalenceandconductionbands.TheabsorptioncoefficientofBiFeO3ceramicsisfoundtobeintherangeof1x10^4cm^-1,indicatingtheefficientabsorptionoflightinthevisibleandultravioletregions. Discussion: ThecalculatedopticalpropertiesofBiFeO3ceramicsareingoodagreementwithexperimentalmeasurements.Theabsorptionbandedgeat3.0eVcorrespondstothebandgapofBiFeO3.ThebroadabsorptionpeakobservedintheimaginarypartofthedielectricfunctionsuggeststhatBiFeO3ceramicshavegreatpotentialasphotocatalystsandsolarenergyconversionmaterials.ThehighabsorptioncoefficientindicatesthatBiFeO3canefficientlycapturephotonsinthevisibleandult