新型二维TM-C-S（TM=Ti, Zr, V, Nb）超导材料的设计及物性调控

二维超导材料由于其独特的结构和电子特性在超导微纳器件中具有重要的实用价值，然而目前已知的二维超导材料超导转变温度较低，限制了其实际应用。因此设计新型二维高温超导材料并探索其超导转变温度的调控手段成为备受关注的超导前沿领域。本项目拟选择第IV、V副族过渡金属碳硫化合物TM-C-S(TM=Ti、Zr、Hf、Nb和Ta等)为切入点，利用基于粒子群优化算法的晶体结构预测技术和基于密度泛函理论的第一性原理计算方法相结合，设计常压下热力学和动力学稳定的新型二维材料，并探索其成为高温超导体的潜力；分析新材料的组分、晶体结构、成键方式、电子和晶格动力学等性质与超导转变温度间的关系，揭示其超导的微观机制；同时采用应力、高压、载流子掺杂、化学吸附等手段对新材料的电子性质和电声耦合相互作用等进行调控，建立调控参量与超导电性的联系，获得提高新材料超导转变温度的最佳调控方案，为探索其它二维高温超导材料提供新思路。

Two-dimensional superconductors possess important practical values owing to the unique structures and electronic properties. However, the known two-dimensional superconductors exhibit the low Tc which limits their practical applications. Therefore, designing novel two-dimensional superconductors and exploring effective methods to enhance the Tc have attracted a lot of attention. Here, using the first principle calculations on the basis of density functional theory, combining the crystal structure prediction technique based on particle swarm optimization algorithm, we design a series of new two-dimensional transition metal carbosulfides which are thermally and dynamically stable, then explore its potential as a high Tc superconductor. Meanwhile, we discuss the relationship between structures, bonding modes, electronic properties, phonon properties and Tc and point out the mechanism for superconductivity. Further, we adjust the electronic properties and Tc of new materials by means of strain, high pressure, carrier doping, and chemical adsorption in order to estabilish the relationship between the regulation parameters and Tc. Finally, the optimal regulation scheme for enhanced Tc of new materials is obtained, which will provide a new idea for exploring other two-dimensional superconductors with high Tc.