论文标题
周期性应变下的二维材料中的拓扑精确的平坦带
Topological exact flat bands in two dimensional materials under periodic strain
论文作者
论文摘要
我们在周期性应变下研究具有二次带交叉点（QBCP）的2D材料中的扁平带及其拓扑。与石墨烯中的狄拉克点（在石墨烯中充当矢量电势）相反，QBCP的应变是Angular Mommentum $ \ ell = 2 $的主管潜力。我们证明，当应变场的优势达到某些``魔术''值时，具有$ c = \ pm 1 $的精确平坦频带在手性极限的电荷中性点上出现，与魔术角扭曲的双层石墨烯相比，这些平面带具有理想的量子，以实现某些互联网和互联网的量子。而且，在整数填充物上，相互作用的哈密顿量是可以解决的。
We study flat bands and their topology in 2D materials with quadratic band crossing points (QBCPs) under periodic strain. In contrast to Dirac points in graphene, where strain acts as a vector potential, strain for QBCPs serves as a director potential with angular momentum $\ell=2$. We prove that when the strengths of the strain fields hit certain ``magic" values, exact flat bands with $C=\pm 1$ emerge at charge neutrality point in the chiral limit, in strong analogy to magic angle twisted bilayer graphene. These flat bands have ideal quantum geometry for the realization of fractional Chern insulators, and they are always fragile topological. The number of flat bands can be doubled for certain point group, and the interacting Hamiltonian is exactly solvable at integer fillings. We further demonstrate the stability of these flat bands against deviations from the chiral limit, and discuss possible realization in 2D materials.
