2021/01/29 by Zeying Zhang, Zhi-Ming Yu, Zhi‐Ming Yu +1
Materials Science · Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Band gap #Brillouin zone #Condensed matter physics #Fermi surface #Graphene research and applications #Mathematics #Physics #Quantum mechanics #Semimetal #Symmetry breaking #Topological Materials and Phenomena #Topological insulator #Topology (electrical circuits) #Weyl semimetal #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.103.115112
10 pages, 8 figures
arxiv created 2021/01/29 · openalex publication_date 2021/03/08 · arxiv updated 2021/05/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Nodal lines, as one-dimensional band degeneracies in momentum space, usually feature a linear energy splitting. Here we propose the concept of magnetic higher-order nodal lines, which are nodal lines with higher-order energy splitting and realized in magnetic systems with broken time-reversal symmetry. We provide sufficient symmetry conditions for stabilizing magnetic quadratic and cubic nodal lines, based on which concrete lattice models are constructed to demonstrate their existence. Unlike its counterpart in nonmagnetic systems, the magnetic quadratic nodal line can exist as the only band degeneracy at the Fermi level. We show that these nodal lines can be accompanied by torus surface states, which form a surface band that span over the whole surface Brillouin zone. Under symmetry breaking, these magnetic nodal lines can be transformed into a variety of interesting topological states, such as three-dimensional quantum anomalous Hall insulator, multiple linear nodal lines, and magnetic triple-Weyl semimetal. The three-dimensional quantum anomalous Hall insulator features a Hall conductivity \ensuremathσxy quantized in units of e2/(hd), where d is the lattice constant normal to the x\text\ensuremath-y plane. Our work reveals previously unknown topological states and offers guidance to search for them in realistic material systems.