Li Yan, Pu Chunying, Zhou Dawei
International Joint Research Laboratory of New Energy Materials and Devices of Henan Province, Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
Henan International Joint Laboratory of MXene Materials Microstructure, College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061, China.
Molecules. 2023 Jul 19;28(14):5522. doi: 10.3390/molecules28145522.
Two-dimensional Janus materials have unique structural characteristics due to their lack of out-of-plane mirror symmetry, resulting in many excellent physical and chemical properties. Using first-principle calculations, we performed a detailed investigation of the possible stable structures and properties of two-dimensional Janus NbSH. We found that both Janus 1T and 2H structures are semiconductors, unlike their metallic counterparts MoSH. Furthermore, we predicted a new stable NbSH monolayer using a particle swarm optimization method combined with first-principle calculations. Interestingly, the out-of-plane mirror symmetry is preserved in this newly found 2D structure. Furthermore, the newly found NbSH is metallic and exhibits intrinsic superconducting behavior. The superconducting critical temperature is about 6.1 K under normal conditions, which is found to be very sensitive to stress. Even under a small compressive strain of 1.08%, the superconducting critical temperature increases to 9.3 K. In addition, the superconductivity was found to mainly originate from Nb atomic vibrations. Our results show the diversity of structures and properties of the two-dimensional Janus transition metal sulfhydrate materials and provide some guidelines for further investigations.
二维Janus材料由于缺乏面外镜像对称性而具有独特的结构特征，从而产生了许多优异的物理和化学性质。我们使用第一性原理计算，对二维Janus NbSH的可能稳定结构和性质进行了详细研究。我们发现，与金属性的MoSH不同，Janus 1T和2H结构均为半导体。此外，我们结合第一性原理计算，采用粒子群优化方法预测了一种新的稳定NbSH单层。有趣的是，在这种新发现的二维结构中保留了面外镜像对称性。此外，新发现的NbSH具有金属性，并表现出本征超导行为。在正常条件下，超导临界温度约为6.1 K，发现其对应力非常敏感。即使在1.08%的小压缩应变下，超导临界温度也会升至9.3 K。此外，发现超导性主要源于Nb原子振动。我们的结果展示了二维Janus过渡金属硫氢化物材料结构和性质的多样性，并为进一步研究提供了一些指导。
