论文标题
三层小型Weyl Phonon
Triple hourglass Weyl phonons
论文作者
论文摘要
晶体固体中具有较高拓扑电荷的非常规的Weyl声子吸引了越来越多的注意力。通过对称分析和低能量$ k.p $有效的哈密顿式，我们提出了对称对称性的三重沙漏Weyl Phonons（Thwps），其Chern Number $ \ Mathcal C $ = $ = $ \ PM $ 3由$ 6_3 $ $ 6_3 $的螺钉旋转在Chiral Space Groups组173（$ p6_3 $）和182 $ P6_32（$）和182 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6 $ p6_33333331_332。我们将liio $ _3 $与太空集团173一起作为候选人，并确认它沿着$ k_z $方向和$ k_x $ -k_y $ plane具有线性和二次分散的THP。由于晶体对称性和拓扑电荷保护的限制，六个等效的单个Weyl Phonon（SWP）出现并位于$ K_z $ = 0平面中。因此，独特的声子表面弧连接了两个THP和6个SWP的投影，从而导致（001）表面布里鲁因区域上的非平凡六倍螺旋表面弧。我们的工作提出了一类拓扑声子，并在逼真的材料中实现了它，为THWP的实验性观察提供了理想的平台。我们希望我们的工作为检测非常规的准颗粒提供了新的想法。
Unconventional Weyl phonons with higher topological charges in crystalline solids have attracted increasing attention. By symmetry analysis and low-energy $k.p$ effective Hamiltonian, we propose the symmetry enforced triple hourglass Weyl phonons (THWPs) with Chern number $\mathcal C$ = $\pm$ 3 protected by $6_3$ screw rotation symmetry in chiral space groups 173 ($P6_3$) and 182 ($P6_322$). We take LiIO$_3$ with space group 173 as a candidate and confirm that it possesses THWP with linear and quadratic dispersions along the $k_z$ direction and in the $k_x$-$k_y$ plane, respectively. Due to the constraints of crystal symmetry and topological charge conservation, six equivalent single Weyl phonons (SWPs) emerge and lie in the $k_z$ = 0 plane. Therefore, the unique phonon surface arcs connect the projections of two THWPs and six SWPs, leading to nontrivial sextuple-helicoid surface arcs on the (001) surface Brillouin zone. Our work proposes a class of topological phonons and realizes it in realistic materials, providing a perfect platform for experimental observation of THWPs. We expect our work to provide a new idea for detection of unconventional quasiparticles.
