Wu Hao-Jia, Wan Yu-Lu, Zeng Zhao-Yi, Hu Cui-E, Chen Xiang-Rong, Geng Hua-Yun
College of Physics, Sichuan University, Chengdu 610064, China.
College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 400047, China.
Phys Chem Chem Phys. 2023 Apr 5;25(14):10143-10154. doi: 10.1039/d3cp00377a.
The structural, electronic, and magnetic properties of vanadium disulfide VS monolayers were investigated using first-principles calculations and Monte Carlo (MC) simulations. The results of molecular dynamics simulations and phonon dispersion showed that the VS monolayer has good dynamic and thermodynamic stabilities. Based on the results of the band structure, we also explore the effect of carrier concentrations on the spin gap, spin polarization and the direction of the easy magnetic axis. Our results demonstrated that doping an appropriate amount of holes can cause the reversal of the easy magnetic axis and maintain nearly 100% spin polarization, which greatly improves the application possibility of the VS monolayer as a spintronic device. The contribution of different orbits to the spin-orbit coupling (SOC) effect is given in magnetocrystalline anisotropy energy, which provides a theoretical basis for explaining the origin of magnetic crystal anisotropy. Based on the MC simulations, we also showed the influences of different parameters (carrier concentrations, magnetic field and crystal field) on the magnetothermal properties of the VS monolayer. It is found that the increase of hole doping concentrations can promote the increase of the Curie temperature, while the increase of electron doping concentrations will greatly weaken the Curie temperature. Furthermore, according to the influences of different parameters on the Curie temperature and spin polarization, we conclude that a suitably enhanced magnetic field and appropriate hole concentrations will not only make the system maintain high spin polarization, but also make the system exhibit ferromagnetic properties above room temperature.
采用第一性原理计算和蒙特卡罗（MC）模拟研究了二硫化钒（VS）单层的结构、电子和磁性性质。分子动力学模拟和声子色散结果表明，VS单层具有良好的动力学和热力学稳定性。基于能带结构的结果，我们还探讨了载流子浓度对自旋能隙、自旋极化和易磁轴方向的影响。我们的结果表明，掺杂适量的空穴可以导致易磁轴反转，并保持近100%的自旋极化，这大大提高了VS单层作为自旋电子器件的应用可能性。磁晶各向异性能给出了不同轨道对自旋轨道耦合（SOC）效应的贡献，为解释磁晶各向异性的起源提供了理论依据。基于MC模拟，我们还展示了不同参数（载流子浓度、磁场和晶体场）对VS单层磁热性质的影响。发现空穴掺杂浓度的增加可以促进居里温度的升高，而电子掺杂浓度的增加将大大削弱居里温度。此外，根据不同参数对居里温度和自旋极化的影响，我们得出结论，适当增强的磁场和合适的空穴浓度不仅会使系统保持高自旋极化，而且会使系统在室温以上表现出铁磁性质。
