(1. 中南大學(xué) 資源加工與生物工程學(xué)院，長沙 410083；
2. 廣西大學(xué) 資源與冶金學(xué)院，南寧 530004)
摘 要: 采用基于密度泛函理論框架下的第一性原理平面波超軟贗勢法，對不同As摻雜濃度FeS2的幾何結(jié)構(gòu)、電子結(jié)構(gòu)和光學(xué)性質(zhì)進(jìn)行計(jì)算和討論。采用2×2×2(Fe32S63As)，2×2×1(Fe16S31As)和2×1×1(Fe8S15As)的超晶胞模型，用1個(gè)As原子取代1個(gè)S原子，使摻雜濃度分別為1.93%、3.82%和7.48%(質(zhì)量分?jǐn)?shù))，然后進(jìn)行3種摻雜體系的計(jì)算，并將其與理想體系進(jìn)行對比。幾何結(jié)構(gòu)與電子結(jié)構(gòu)的計(jì)算結(jié)果表明：As摻雜使得FeS2的晶格常數(shù)和晶胞體積增大，導(dǎo)帶部分下移，禁帶寬度減小，并且在-10.4~-9.5 eV的淺部價(jià)帶產(chǎn)生了由As的p態(tài)貢獻(xiàn)的雜質(zhì)能級(jí)。光學(xué)性質(zhì)計(jì)算結(jié)果表明，摻雜后Fe(S1-xAsx)2的靜態(tài)介電常數(shù)、折射率和光電導(dǎo)率在一定范圍內(nèi)均隨著摻雜量的增大而明顯增大，說明As摻雜顯著增強(qiáng)了FeS2對光的吸收以及光電轉(zhuǎn)換效率。
關(guān)鍵字: As摻雜；黃鐵礦；光電性質(zhì)；第一性原理
（1. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China;
2. College of Resources and Metallurgy, Guangxi University, Nanning 530004, China）
Abstract:Aimed at verifying the effect of As doping concentration on FeS2, geometrical structure, electronic structure and optical properties of As-doped FeS2 were calculated using pseudo-potential plane-wave method of the first principle based on the density function theory. Three supercells (2×2×2, 2×2×1 and 2×1×1) were introduced to achieve different doping concentrations (1.93%, 3.82% and 7.48%, mass fraction). The results of geometrical structure, electronic structure show that lattice constant and volume of unit cell increase with As addition, the conduction band moves negatively while the width of forbidden band decreases. Moreover, the density of states in the range of -10.4 - -9.5 eV exhibits impurity level composed of As p. The calculation of optical properties reveals the static dielectric constant, refractive index and photo conductivity aggrandize with the ever-increasing doping concentration, which indicates FeS2 doped As possesses stronger absorption capacity of light and higher photoelectric conversion efficiency. Therefore, the calculation lays some theory foundation for exploitation and development of FeS2 photoelectric materials.
Key words: As-doping; pyrite; optical and electrical property; first principle
