Abstract Systematic density functional theory calculations were carried out to study the structural, electronic, magnetic and optical properties of vacancy and antisite defects in marcasite FeS2 (m-FeS2). Five types of point defects were considered, that is S vacancy, Fe vacancy, FeS divacancy, Fe substitute S site and S substitute Fe site. The results show that Fe substitute S, S vacancy and Fe vacancy are the dominant defects in m-FeS2. The defects remarkably affect the electrical, optical performances of the m-FeS2, and even induce magnetism. All the considered point defects have defect states in the band gap of perfect m-FeS2. We estimated the stability of magnetic state and found that the m-FeS2 with point defects shows magnetic ground state except S vacancy case. Detailed analysis shows that m-FeS2 with S vacancy is a nonmagnetic semiconductor, with Fe vacancy, FeS divacancy and Fe substitute S site become magnetic metal while with S substitute Fe site is a magnetic semiconductor. In addition, compared with perfect m-FeS2, the static dielectric constants and static refractive indexes of m-FeS2 with defects are all increased significantly, the absorption coefficients show red shifts and enhancements in the infrared region due to the defect states.

中文翻译：

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本征点缺陷对白铁矿 FeS2 结构、电子、磁性和光学性质的影响

摘要 通过系统密度泛函理论计算，研究了白铁矿FeS2 (m-FeS2)中空位和反位缺陷的结构、电子、磁性和光学性质。考虑了五种类型的点缺陷，即S空位、Fe空位、FeS双空位、Fe替代S位和S替代Fe位。结果表明，Fe替代S、S空位和Fe空位是m-FeS2中的主要缺陷。这些缺陷显着影响 m-FeS2 的电学、光学性能，甚至诱发磁性。所有考虑的点缺陷都在完美 m-FeS2 的带隙中具有缺陷状态。我们估计了磁态的稳定性，发现除了 S 空位情况外，具有点缺陷的 m-FeS2 显示出磁基态。详细分析表明，含S空位的m-FeS2为非磁性半导体，含Fe空位、FeS双空位和Fe替代S位成为磁性金属，而含S替代Fe位则为磁性半导体。此外，与完美的 m-FeS2 相比，有缺陷的 m-FeS2 的静态介电常数和静态折射率均显着增加，由于缺陷态，吸收系数在红外区域出现红移和增强。