By combining the GGA + U method, the magnetic and optical properties of (In, Mn) co-doped 4H–SiC and (In, 2Mn) co-doped 4H–SiC systems are calculated by first principles. The results show that the local magnetic moment of the (In, Mn) co-doped 4H–SiC system is 5.14 μ_B. And (In, 2Mn) co-doped 4H–SiC system can get the most stable ferromagnetic state, in which the energy difference △ E_FM is 172.2 meV. The ferromagnetism of (In, 2Mn) co-doped 4H–SiC comes from the strong hybridization between the Si:2p orbitals, the C:2p orbitals and the Mn:3d orbitals near the dopant. In addition, the introduction of dopant atoms can reduce the band gap and improve conductivity. The doping system can weaken the maximum dielectric peak, thereby weakening the electromagnetic absorption ability of ϵ₁(ω) in 4H–SiC. The doped system shows a red shift. And the doping system has lower transmittance in the infrared and visible regions. Our results show that doping 4H–SiC with In and Mn atoms is an effective method to modulate the magnetic and optical properties of 4H–SiC. Keywords: First principle, Magnetism, Optical properties, 4H–SiC.

通过结合 GGA + U 方法，(In, Mn) 共掺杂 4H-SiC 和 (In, 2Mn) 共掺杂 4H-SiC 系统的磁和光学性质由第一性原理计算。结果表明，(In, Mn) 共掺杂 4H-SiC 体系的局部磁矩为 5.14 μ _B。并且(In, 2Mn)共掺杂4H-SiC体系可以获得最稳定的铁磁态，其中能量差△E _FM为172.2 meV。(In, 2Mn) 共掺杂 4H-SiC 的铁磁性来自掺杂剂附近的 Si:2p 轨道、C:2p 轨道和 Mn:3d 轨道之间的强杂化。此外，掺杂原子的引入可以减小带隙并提高导电性。掺杂体系可以削弱最大介电峰值，从而削弱 ϵ 的电磁吸收能力₁ (ω) 在 4H-SiC 中。掺杂系统显示红移。并且掺杂体系在红外和可见光区域的透射率较低。我们的结果表明，用 In 和 Mn 原子掺杂 4H-SiC 是调节 4H-SiC 磁性和光学性能的有效方法。关键词：第一性原理，磁性，光学特性，4H-SiC。