Wang Zijin, Qureshi Ali Hamza, Duan Yuanyuan, Liu Yujie, Wang Yanbiao, Zhu Jun, Lu Jinlian, Guo Tianxia, Liu Yongjun, Zhang Xiuyun
College of Physics Science and Technology, Yangzhou University, Yangzhou 225002, China.
Department of Fundamental Courses, Wuxi Institute of Technology, Wuxi 214121, China.
Molecules. 2024 Aug 19;29(16):3915. doi: 10.3390/molecules29163915.
Two-dimensional (2D) ferromagnetic semiconductors (FM SCs) provide an ideal platform for the development of quantum information technology in nanoscale devices. However, many developed 2D FM materials present a very low Curie temperature (T), greatly limiting their application in spintronic devices. In this work, we predict two stable 2D transition metal chalcogenides, VSeX (X = S, Te) monolayers, by using first-principles calculations. Our results show that the VSeTe monolayer is a robust bipolar magnetic SC with a moderate bandgap of 0.53 eV, while VSeS is a direct band-gap FM SC with a bandgap of 0.59 eV. Interestingly, the ferromagnetisms of both monolayers are robust due to the V-S/Se/Te-V superexchange interaction, and Ts are about 406 K and 301 K, respectively. Applying biaxial strains, the FM SC to antiferromagnetic (AFM) SC transition is revealed at 5% and 3% of biaxial tensile strain. In addition, their high mechanical, dynamical, and thermal stabilities are further verified by phonon dispersion calculations and ab initio molecular dynamics (AIMD) calculations. Their outstanding attributes render the VSeY (Y = S, Te) monolayers promising candidates as 2D FM SCs for a wide range of applications.
二维（2D）铁磁半导体（FM SCs）为纳米级器件中的量子信息技术发展提供了一个理想平台。然而，许多已开发的二维铁磁材料呈现出非常低的居里温度（T），极大地限制了它们在自旋电子器件中的应用。在这项工作中，我们通过第一性原理计算预测了两种稳定的二维过渡金属硫族化合物，VSeX（X = S，Te）单层。我们的结果表明，VSeTe单层是一种稳健的双极磁性半导体，具有0.53 eV的适中带隙，而VSeS是一种直接带隙铁磁半导体，带隙为0.59 eV。有趣的是，由于V-S/Se/Te-V超交换相互作用，两种单层的铁磁性都很稳健，居里温度分别约为406 K和301 K。施加双轴应变时，在双轴拉伸应变达到5%和3%时会出现从铁磁半导体到反铁磁（AFM）半导体的转变。此外，通过声子色散计算和从头算分子动力学（AIMD）计算进一步验证了它们的高机械、动力学和热稳定性。它们出色的特性使VSeY（Y = S，Te）单层有希望成为适用于广泛应用的二维铁磁半导体候选材料。
