虽然已知双层Bi $_2$ Sr $_2$ CaCu $_2$ O $_{8+y}$（BSCCO）铜酸盐超导体表现出一维（1D）无公度超晶格（IS），但IS对电子结构的影响仍然难以捉摸。随着最近的兴趣从欠掺杂到最佳和过掺杂相的BSCCO通过增加空穴掺杂$x$，控制的氧电子浓度$y$，在这里，我们专注于多重分裂的态密度（DOS）峰和出现的高阶范霍夫奇异性（VHS）由于一维无公度超晶格。已知1D无公度波矢量$\textbf{q} = ε\textbf{b}$（其中$\textbf{b}$是正交晶格的倒易晶格矢量）由BSCCO中的$0.209$- $0.215$范围内和Bi中的$_2$-$_{8+y}$范围内的不同原子层之间的失配应变控制。本工作报告的理论计算的复杂图案的VHS由于一维无公度超晶格与大的一维准公度超晶胞与波矢$ε=9/η$的范围$36 > η> 43$。讨论了由于应变扭曲双层石墨烯中的莫尔{é}晶格，在具有VHS的失配CuOPDMATHABMM双层膜中复杂VHS分裂和出现高阶VHS的相似性。这使得不匹配的CuO $_2$双层膜非常有希望用于构建具有调谐物理特性的量子器件。
英文摘要：
While it is known that the double-layer Bi$_2$Sr$_2$CaCu$_2$O$_{8+y}$ (BSCCO) cuprate superconductor exhibits a one-dimensional (1D) incommensurate superlattice (IS), the effect of IS on the electronic structure remains elusive. Following the recent shift of the interest from underdoped to optimum and overdoped phase in BSCCO by increasing the hole doping $x$, controlled by the oxygen interstitials concentration $y$, here we focus on the multiple splitting of the density of states (DOS) peaks and emergence of higher order van Hove singularities (VHS) due to the 1D incommensurate superlattice. It is known that 1D incommensurate wave vector $\textbf{q} = ε\textbf{b}$ (where $\textbf{b}$ is the reciprocal lattice vector of the orthorhombic lattice) is controlled by the misfit strain between different atomic layers in the range $0.209$ - $0.215$ in BSCCO and in the range $0.209$ - $0.25$ in Bi$_2$Sr$_2$Ca$_{1-x}$Y$_x$Cu$_2$O$_{8+y}$ (BSCYCO). This work reports the theoretical calculation of a complex pattern of VHS due to the 1D incommensurate superlattice with large 1D quasi-commensurate supercells with the wave vector $ε=9/η$ in the range $36 > η> 43$. The similarity of the complex VHS splitting and appearing of higher order VHS in a mismatched CuO$_2$ bilayer with VHS due to the moir{é} lattice in strained twisted bilayer graphene is discussed. This makes mismatched CuO$_2$ bilayer quite promising for constructing quantum devices with tuned physical characteristics.
Relativistic Mott transition and high-order van Hove singularity in twisted double bilayer WSe${}_2$: mean-field and functional renormalization group study
Van Hove Singularity-Driven Topological Magnetism in Twisted MoTe2
University of Washington（华盛顿大学）；Harvard University（哈佛大学）；Massachusetts Institute of Technology（麻省理工学院）；University of California - Santa Barbara（加利福尼亚大学圣巴巴拉分校）；National Institute for Materials Science（国立材料研究所）
Competing instabilities of the extended Hubbard model on the triangular lattice: Truncated-unity functional renormalization group and application to moiré materials
