过渡金属 X（ X=Cr、Mn、Fe、Tc、Re ）掺杂Janus Ga2SSe 的第一性原理研究

利用密度泛函理论的第一性原理赝势平面波方法，研究过渡金属X(X=Cr、Mn、Fe、Tc、Re)原子掺杂Janus Ga₂SSe的磁性、电子性质及光学性质.研究表明：过渡金属掺杂Janus Ga₂SSe体系在Chalcogen-rich条件下有着比Ga-rich条件下更好的稳定性.其中Mn掺杂体系形成能在两种条件下皆为最低.本征Ga₂SSe是具有2.02 eV带隙的间接带隙半导体，在紫外区域有着很好的光伏吸收能力.与本征Ga₂SSe相比，Cr掺杂体系自旋向上通道出现杂质能级，自旋向上与向下通道不对称，呈磁矩为2.797μ_B铁磁性半金属. Mn掺杂体系在其自旋向上通道产生的杂质能级，呈磁矩为3.645μ_B的磁性P型半导体. Fe掺杂体系自旋向下通道产生的杂质能级，呈磁矩为3.748μ_B磁性P型半导体.在Tc与Re掺杂后，带隙皆由间接变直接带隙，呈无磁性的P型半导体.从光学性质来看，各掺杂体系与未掺杂Ga₂SSe在介电...

First-principles study on the transition metal atoms X (X = Mn, Tc, Re) doped Janus Ga2SSe materials

The magnetic, electronic, and optical properties of transition metal X (X=Cr, Mn, Fe, Tc, Re) atomically doped Janus Ga2SSe are investigated using the first-principles plane-wave method based on the density functional theory. It’s shown that the transition metal-doped Janus Ga2SSe systems have better stability under Chalcogen-rich condition than under Ga-rich condition. The Mn-doped system has the lowest formation energy under both conditions. The intrinsic Ga2SSe is an indirect bandgap semiconductor with a bandgap of 2.02 eV and has good photovoltaic absorption in the ultraviolet (UV) region. Compared with the intrinsic Ga2SSe, the impurity energy levels appear in the spin-up channel of the Cr-doped system, which makes the spin-up and spin-down channels asymmetric, and presents the ferromagnetic semimetal property with a magnetic moment of 2.797 μB. The impurity energy levels appear in the spin-up channel of the Mn-doped system, making the system become a magnetic P-type semiconductor with a magnetic moment of 3.645 μB. The impurity energy level appears in the spin-down channel of the Fe-doped system, making the system become a P-type semiconductor with a magnetic moment of 3.748 μB magnetic. After doping of Tc and Re, the band gaps are changed from indirect to direct band gaps, and both systems are non-magnetic P-type semiconductors. In terms of optical properties, each doped system has significantly enhanced dielectric constant and refractive coefficient compared with undoped Ga2SSe, and the absorption coefficient appears blue-shifted in the high energy region (3-10 eV). It has potential applications in the field of UV detectors and photovoltaic absorption.