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本文采用基于密度泛函理论和平面波方法,计算了δ-V2O_5,ζ-Nb_2O_5和B-Ta_2O_5的电子结构、弹性性质、高温下的最小热导率以及光学性质.研究表明M2O_5(M=V,Nb,Ta)包含共价键和离子键.材料力学性质的优良性、硬度以及韧性都按ζ-Nb_2O_5→B-Ta_2O_5→δ-V2O_5的顺序增加.M2O_5(M=V,Nb,Ta)都有非常显著的弹性各向异性.而这三种材料在高温下都有较低的热导率,并且基于杨氏模量的Clark模型计算得到的三维热导率图形在各个晶向上都呈各向异性.δ-V2O_5,ζ-Nb_2O_5和B-Ta_2O_5的静介电常数分别为7.89、4.78和4.01.δ-V2O_5在长波长范围内展现出较好的吸收性质,而且波长范围扩展到了614 nm.与ζ-Nb_2O_5和B-Ta_2O_5相比,在红外和可见光区δ-V2O_5的反射率和折射率较大.在小于394 nm的波长范围内,δ-V2O_5和B-Ta_2O_5分别出现了折射率的最大值和最小值.且M2O_5(M=V,Nb,Ta)在可见光区域的损失函数都非常小,而在6.00.17.00 eV范围内出现了最大值.
In this paper, the electronic structures, elastic properties, minimum thermal conductivity at high temperature and optical properties of δ-V2O5, ζ-Nb2O5 and B-Ta2O5 have been calculated based on density functional theory and plane wave method. Nb, Ta) contains both covalent and ionic bonds.The excellent mechanical properties, hardness and toughness of the materials increase in the order of ζ-Nb 2 O 5 → B-Ta 2 O 5 → δ-V 2 O 5 .M 2 O 5 (M = V, Nb, Ta) Have very significant elastic anisotropy, and all three materials have lower thermal conductivity at high temperature, and the three-dimensional thermal conductivity graph calculated based on Young’s modulus Clark model shows a The dielectric anisotropy of δ-V2O5, ζ-Nb2O5 and B-Ta2O5 are 7.89, 4.78 and 4.01, respectively. Δ-V2O5 exhibits good absorption properties in the long wavelength range and the wavelength range extends to 614 nm Compared with ζ-Nb 2 O 5 and B-Ta 2 O 5, the reflectivity and refractive index of δ-V 2 O 5 in the infrared and visible regions are larger than that of ζ-Nb 2 O 5 and B-Ta 2 O 5, respectively. In the wavelength range less than 394 nm, (M = V, Nb, Ta) in the visible region is very small 6.00.17.00 eV emerged within the range of the maximum value.