A first-principles theoretical study of the enhanced electronic and magnetic properties of a single-layer CdS (denoted as SL-CdS) was conducted via Li substitutional doping at possible sites. Previous work shows that SL-CdS is a non-magnetic and direct bandgap semiconductor. Our work demonstrated that electronic bandgap tuned to smaller and larger values, e.g., the calculated bandgap (pseudo bandgap) for Li_Cd (Li_h) are 1.80 eV and 1.62 eV, respectively. Local magnetic moment induced via Li atomic doping at possible dopants sites except for Li_h. The Li_Cd gives a maximum magnetic moment of 0.98 μ_B and shows the half-metallic character with a small dispersion for the spin-down channel at the Γ point. Among all the possible sites, the Li_Cd in SL-CdS is magnetic and being most favorable thermodynamically under both S-rich and Cd-rich conditions. The Li_Cd in SL-CdS indicates spin polarization with increased bandgap for spin-up and spin-down channels. In contrast, the Li_S induces a magnetic moment of 0.86 μ_B with a reduced bandgap of 0.60 eV for both the spin-up and spin-down channels. The partial magnetic moment is due to the fact small concentration of the dopant. Interestingly, Li_h in SL-CdS shows non-magnetic semiconducting nature with decreased bandgap. For further investigation, we considered the most favorable Cd-Site. For room-temperature ferromagnetism, we did ferromagnetic and anti-ferromagnetic calculations. We considered interactions between two Li atoms substituted at far positions (1, 2) and near positions (1, 3) in SL-CdS. It was found that 2Li_Cd in SL-CdS at near positions (1, 3) has FM order with Curie temperature (T_c) of 339.95 K at − 5% compressive biaxial strain. The effect of Li doping on electronic and magnetic properties of SL-CdS can help to utilize SL-CdS materials in electronics and spintronics devices applications.

通过在可能的位置进行 Li 置换掺杂，对单层 CdS（表示为 SL-CdS）的增强的电子和磁性能进行了第一性原理理论研究。先前的工作表明 SL-CdS 是一种非磁性和直接带隙半导体。我们的工作表明，电子带隙调整到更小和更大的值，例如，Li _Cd (Li _h )的计算带隙（伪带隙）分别为1.80 eV 和 1.62 eV。在除了 Li _h之外的可能的掺杂位置通过 Li 原子掺杂引起的局部磁矩。Li _Cd的最大磁矩为 0.98 μ _B并显示了半金属特性，在 Γ 点处的自旋向下通道具有小的色散。在所有可能的位置中，SL-CdS 中的 Li _Cd是磁性的，并且在富含 S 和富含 Cd 的条件下在热力学上是最有利的。SL-CdS 中的 Li _Cd表明自旋极化，自旋向上和自旋向下通道的带隙增加。相比之下，Li _S在自旋向上和自旋向下通道中感应出 0.86 μ _{B 的}磁矩，带隙减小 0.60 eV。部分磁矩是由于掺杂剂的浓度小。有趣的是，李_赫在 SL-CdS 中显示出带隙减小的非磁性半导体性质。为了进一步调查，我们考虑了最有利的 Cd 位点。对于室温铁磁性，我们进行了铁磁和反铁磁计算。我们考虑了在 SL-CdS 中远位置 (1, 2) 和近位置 (1, 3) 处取代的两个锂原子之间的相互作用。发现SL-CdS 中靠近位置 (1, 3) 的2Li _Cd具有 FM 阶，居里温度 ( T _c ) 为 339.95 K，在 - 5 %压缩双轴应变下。Li掺杂对SL-CdS的电子和磁性能的影响有助于在电子和自旋电子器件应用中利用SL-CdS材料。