Chiral charge density wave (CDW) is widely observed in low dimensional systems to be entangled with various emerging phases but its microscopic origin has been elusive. We reinvestigate the representative but debated chiral CDW of TiSe$_{2}$ using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. Our STM data reveal unambiguously the chiral distortion of the topmost Se layer in domains of opposite chirality, which are interfaced with a novel domain wall. DFT calculations find the atomic structure of the chiral CDW, which has a $C2$ symmetry with the inversion and reflection symmetry broken. The chirality is determined by the helicity of Se-Ti bond distortions and their translation between neighboring layers. The present structure reproduces well the STM images with lower energy than the prevailing non-chiral $P\bar{3}c1$ structure model. Our result provides the atomistic understanding of the CDW chirality in TiSe$_{2}$, which can be referred to in a wide class of monolayer and layered materials with CDW.
Microscopic Theory of the Phonon Thermal Hall Effect in Chiral Mott Insulators
Seoul National University（首尔大学）；Soongsil University（崇实大学）；Origin of Matter and Evolution of Galaxies (OMEG) institute, Soongsil University（崇实大学物质起源与星系演化研究所）
Skyrmion and Meron Crystals in Intermetallic Gd$_3$Ru$_4$Al$_{12}$: Microscopic Model Insights into Chiral Phases
University of Science and Technology of China（中国科学技术大学）；University of Tennessee（田纳西大学）；Oak Ridge National Laboratory（橡树岭国家实验室）；RIKEN Center for Emergent Matter Science (CEMS)（理化学研究所新兴物质科学中心）；Los Alamos National Laboratory（洛斯阿拉莫斯国家实验室）；The University of Tokyo（东京大学）
Microscopic origin of the linear temperature increase of the magnetic susceptibility of BaFe$_{2}$As$_{2}$
结合\emph{ab initio}能带结构理论和动力学平均场论，我们解释了实验观察到的铁磷属元素化物材料BaFe $_{2}$ As $_{2}$磁化率的线性温度增加。这种异常行为的微观起源被追溯到一个尖锐的峰值在光谱函数位于费米能级以下约100毫电子伏。该峰是由于与磷属元素化物的层状晶体结构相关联的二维带的弱色散。
