Two-dimensional (2D) materials that exhibit charge density waves (CDWs) have generated many research endeavors in the hopes of employing their exotic properties for various quantum-based technologies. Early investigations surrounding CDWs were mostly focused on bulk materials. However, applications for quantum devices have since required devices to be constructed from few-layer material to fully utilize the material's properties. This field has greatly expanded over the decades, warranting a focus on the computational efforts surrounding CDWs in 2D materials. In this review, we will cover ground in the following relevant, theory-driven subtopics for TaS2 and TaSe2: summary of general computational techniques and methods, atomic structures, Raman modes, and effects of confinement and dimensionality. Through understanding how the computational methods have enabled incredible advancements in quantum materials, one may anticipate the ever-expanding directions available for continued pursuit as the field brings us through the 21st century.
A Review on Improving PSC Performance through Charge Carrier Management: Where We Stand and What's Next?
S.U. Umarov Physical-Technical Institute of NAST（NAST S.U. 乌马尔物理技术研究所）；School of Optoelectronic Engineering & CQUPT-BUL Innovation Institute, Chongqing University of Posts and Telecommunications（重庆邮电大学光电工程学院及CQUPT-BUL创新学院）
Reentrant Quantum Spin Hall States in Charge Density Wave Phase of Doped Single-Layer Transition Metal Dichalcogenides
利用第一性原理计算方法，我们揭示了单层1 T $'$ -MoTe $_2$和1 T $'$ -WTe $_2$在无掺杂时呈现量子自旋霍尔（QSH）边缘态的一系列相变随电子掺杂的变化.随着掺杂的增加，我们发现声子介导的超导相首先实现，其次是一个电荷密度波（CDW）相与非对称晶格对称性。新发现的CDW相显示狄拉克或外尔能带的自旋轨道耦合的分数带填充的情况下，重新进入拓扑绝缘相与完全填充的带。与CDW相共存的QSH态的强劲复苏被证明是源于通过强电子-声子相互作用引起的非对称晶格畸变引起的能带反转，从而表明仅通过掺杂就可以在二维晶体上实现超导，密度波和拓扑态之间的各种界面态。
