Cu_(3)NbTe_(4)中高对称线上二次节点线声子  

Quadratic nodal line phonons along high-symmetry lines in Cu_(3)NbTe_(4)

作　　者：杨志勇 黄可欣 郭华 郑宝兵 常少梅 YANG Zhi-yong;HUANG Ke-xin;GUO Hua;ZHENG Bao-bing;CHANG Shao-mei(Institute of Physics and Optoelectronics Technology,Baoji University of Arts and Sciences,Baoji 721016,Shaanxi,China)

机构地区：[1]宝鸡文理学院物理与光电技术学院,陕西宝鸡721016

出　　处：《宝鸡文理学院学报（自然科学版）》2024年第3期37-42,49,共7页Journal of Baoji University of Arts and Sciences(Natural Science Edition)

基　　金：陕西省自然科学基础研究计划资助项目(2022JM-001);宝鸡文理学院研究生创新科研项目(YJSCX23YB35)。

摘　　要：目的明确固体材料中存在于高对称线上的二次节点线拓扑声子。方法采用基于密度泛函理论的第一性原理计算方法得到声子谱,利用基于力常数构建的声子紧束缚哈密顿量计算材料的拓扑性质。结果系统地研究了Cu_(3)NbTe_(4)中存在的拓扑声子性质。在Cu_(3)NbTe_(4)声子谱的高频区发现了二次型的能带交叉。利用紧束缚哈密顿量计算了与第22声子带有关的所有节点和布里渊区R点附近的三维声子谱投影表示,这些二次节点线在布里渊区中形成了节点笼的形状。最后,计算了其在(010)平面投影的表面态和等频率表面弧。结论证实了固体材料Cu_(3)NbTe_(4)中高对称线上二次节点线的存在,其清晰的表面态和等频率表面弧有助于实验上的观测。Purposes—To clarify the quadratic nodal line topological phonons along the high-symmetry lines in solid materials.Methods—The first-principles calculations method based on density functional theory are used to obtain the phonon spectrum,and the phonon tight-binding Hamiltonian constructed based on force constants is used to calculate the topological properties of the material.Results—The topological properties in Cu_(3)NbTe_(4)are systematically studied.Quadratic band crossings are found in the high-frequency region of phonon spectrum in Cu_(3)NbTe_(4).The tight-binding Hamiltonian is used to uncover all nodes associated with the 22nd phonon band and calculate the three-dimensional representations of the phonon spectrum near the R point in the Brillouin zone.These quadratic nodal lines form the shape of a node cage in the Brillouin zone.Finally,the surface states and iso-frequency surface arcs projected on the(010)plane are calculated.Conclusions—The existence of quadratic nodal lines on the high-symmetry line of the solid material Cu_(3)NbTe_(4)is confirmed,and its clear surface states and iso-frequency surface arcs are helpful for experimental observations.

关 键 词：第一性原理计算 Cu_(3)NbTe_(4) 二次节点线声子 表面态 

分 类 号：O469[理学—凝聚态物理]