２次元物質ゲルマネンの実デバイス環境下における電子状態・輸送特性の理論研究

石墨烯的缺点促使科学家研究石墨烯以外的新型2D材料。锗和单烯具有各种迷人的性质，如狄拉克锥体、超高的载流子迁移率和量子自旋霍尔效应。虽然在实验中已经在几种底物上合成了它们，但仍然缺乏合适的底物来保持吸引人的狄拉克-锥和QSHE。通过将密度泛函理论与材料信息学相结合，我们从数据库中的185,000多个条目中找到了几种适合于日耳烯和斯坦烯的底物。我们的模型分析表明，衬底与靶2D材料之间的相互作用等同于赝电场。(物理评论B，96,075427)此外，我们正在实施机器学习方法，以提供准确和快速的2D材料沉积过程的模拟。除了原来的计划外，我们还关注过渡金属二卤化物(TMDS)家族的成员WTe2。由于奇异的非饱和磁阻(MR)和可能的II型Weyl锥，它已经成为2D材料中的一颗冉冉升起的新星。然而，对于WTe2的表面弛豫和表面电子结构的研究还很少，尤其是对少数几层板材。为了解决这些问题，我们研究了几层WTe2(应用物理快报，10,045702；ACSNano，11,11459)中精确的表面弛豫和机械可调的电子结构。关于在少层WTe2中发现的机械可调谐表面偶极子的研究正在准备中。

The drawbacks of graphene stimulate scientists to investigate novel 2D materials beyond graphene. Germanene and stanene have various fascinating properties, such as the Dirac-cone, ultrahigh carrier mobility, and the quantum spin Hall effect (QSHE). While they have been synthesized on several substrates in experiment, there is still a lack of suitable substrates to preserve the attractive Dirac-cone and QSHE. By combining DFT with materials informatics, we have found several suitable substrates for germanene and stanene from more than 185, 000 entries in the database. The interaction between the substrate and the target 2D materials is equivalent to pseudoelectric field, as revealed by our model analysis. (Physical Review B, 96, 075427) Furthermore, we are implementing a machine learning approach to provide accurate and fast simulation of the deposition procedure of 2D materials.In addition to the original plan, we also put our eyes on WTe2, a member of transition metal dichalcogenides (TMDs) family. It has been a rising star in 2D materials due to the exotic non-saturating magnetoresistance (MR) and the possible type-II Weyl cone. However, the study about the surface relaxation and surface electronic structure is insufficient in WTe2, especially for few layer slabs. To solve the problems, we have investigated the accurate surface relaxation and mechanically tunable electronic structure in few-layer WTe2 (Applied Physics Express, 10, 045702; ACS Nano, 11, 11459). The research about the mechanically tunable surface dipole found in few-layer WTe2 is in preparation.