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采用基于密度泛函理论的第一性原理方法研究了Zintl相Sr_3Ga_2M_4(M=P,As)的电子结构和成键特征.计算得到的晶格常数和实验符合得很好,确保了计算的准确性.相似的态密度表明两种化合物能带结构近似,Sr_3Ga_2P_4和Sr_3Ga_2As_4的带隙分别为0.99eV和0.74eV,价带顶最高点和最低点分别位于Γ点和X点说明材料为窄带隙间接半导体,满足对热电材料的带隙要求.利用电子局域函数分析其成键特性,晶体结构内部展现出共价键和离子键的共存,符合Zintl相材料成键特征,这种复杂的结构有利于材料的低热导率.对有效质量的分析和计算进一步表明材料具有潜在的热电特性.
The electronic structure and bonding characteristics of the Zintl phase Sr_3Ga_2M_4 (M = P, As) were investigated by the first-principles method based on the density functional theory. The calculated lattice constants are in good agreement with the experimental results, ensuring accurate calculation The similar state density indicates that the band structures of the two compounds are similar, the band gaps of Sr_3Ga_2P_4 and Sr_3Ga_2As_4 are 0.99eV and 0.74eV, respectively. The highest and lowest valence bands are located at Γ and X points, respectively. Semiconductor to meet the bandgap requirements of thermoelectric materials.Using electronic local function analysis of its bonding properties, the coexistence of covalent and ionic bonds within the crystal structure shows coexistence with the bond of Zintl phase material, this complex structure has Conducive to the low thermal conductivity of the material, the analysis and calculation of effective mass further indicates that the material has potential thermoelectric properties.