Meftakhutdinov Ruslan M, Sibatov Renat T
Laboratory of Diffusion Processes, Ulyanovsk State University, 432017 Ulyanovsk, Russia.
Scientific-Manufacturing Complex "Technological Centre", 124498 Moscow, Russia.
Nanomaterials (Basel). 2022 Nov 5;12(21):3904. doi: 10.3390/nano12213904.
Novel representative 2D materials of the Janus type family X-M-ZN2 are studied. These materials are hybrids of a transition metal dichalcogenide and a material from the MoSi2N4 family, and they were constructed and optimized from the MoSi2N4 monolayer by the substitution of SiN2 group on one side by chalcogen atoms (sulfur, selenium, or tellurium), and possibly replacing molybdenum (Mo) to tungsten (W) and/or silicon (Si) to germanium (Ge). The stability of novel materials is evaluated by calculating phonon spectra and binding energies. Mechanical, electronic, and optical characteristics are calculated by methods based on the density functional theory. All considered 2D materials are semiconductors with a substantial bandgap (>1 eV). The mirror symmetry breaking is the cause of a significant built-in electric field and intrinsic dipole moment. The spin−orbit coupling (SOC) is estimated by calculations of SOC polarized bandstructures for four most stable X-M-ZN2 structures. The possible van der Waals heterostructures of considered Janus type monolayers with graphene are constructed and optimized. It is demonstrated that monolayers can serve as outer plates in conducting layers (with graphene) for shielding a constant external electric field.
研究了Janus型家族X-M-ZN2的新型代表性二维材料。这些材料是过渡金属二硫属化物与MoSi2N4家族材料的杂化物，它们是通过用硫族原子（硫、硒或碲）取代一侧的SiN2基团，并可能将钼（Mo）替换为钨（W）和/或将硅（Si）替换为锗（Ge），从MoSi2N4单层构建并优化得到的。通过计算声子谱和结合能来评估新型材料的稳定性。基于密度泛函理论的方法计算机械、电子和光学特性。所有考虑的二维材料都是具有较大带隙（>1 eV）的半导体。镜面对称性破缺是显著内建电场和固有偶极矩的原因。通过计算四种最稳定的X-M-ZN2结构的自旋轨道耦合（SOC）极化能带结构来估计自旋轨道耦合。构建并优化了所考虑的Janus型单层与石墨烯可能的范德华异质结构。结果表明，单层可以用作导电层（与石墨烯）中的外板，以屏蔽恒定的外部电场。
