TY - JOUR
T1 - Three-dimensional higher-order saddle-point-induced flatbands in Co-based kagome metals
AU - Tan, Hengxin
AU - Jiang, Yiyang
AU - McCandless, Gregory T.
AU - Chan, Julia Y.
AU - Yan, Binghai
N1 - Publisher Copyright: © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
PY - 2024/11
Y1 - 2024/11
N2 - The saddle point (Van Hove singularity) exhibits a divergent density of states in two-dimensional systems, leading to fascinating phenomena such as strong correlations and unconventional superconductivity, yet it is seldom observed in three-dimensional (3D) systems. In this work we find two types of 3D higher-order saddle points (HOSPs) in emerging 3D kagome metals YbCo6Ge6 and MgCo6Ge6. Both HOSPs exhibit a singularity in their density of states, which is significantly enhanced compared to the ordinary saddle point. The HOSP near the Fermi energy generates a flatband extending a large area in the Brillouin zone, potentially amplifying the correlation effect and fostering electronic instabilities. Two types of HOSPs exhibit distinct robustness upon element substitution and lattice distortions in these kagome compounds. Our work paves the way for engineering exotic band structures, such as saddle points and flatbands, and exploring interesting phenomena in Co-based kagome materials.
AB - The saddle point (Van Hove singularity) exhibits a divergent density of states in two-dimensional systems, leading to fascinating phenomena such as strong correlations and unconventional superconductivity, yet it is seldom observed in three-dimensional (3D) systems. In this work we find two types of 3D higher-order saddle points (HOSPs) in emerging 3D kagome metals YbCo6Ge6 and MgCo6Ge6. Both HOSPs exhibit a singularity in their density of states, which is significantly enhanced compared to the ordinary saddle point. The HOSP near the Fermi energy generates a flatband extending a large area in the Brillouin zone, potentially amplifying the correlation effect and fostering electronic instabilities. Two types of HOSPs exhibit distinct robustness upon element substitution and lattice distortions in these kagome compounds. Our work paves the way for engineering exotic band structures, such as saddle points and flatbands, and exploring interesting phenomena in Co-based kagome materials.
UR - http://www.scopus.com/inward/record.url?scp=85209633209&partnerID=8YFLogxK
U2 - https://doi.org/10.1103/PhysRevResearch.6.043132
DO - https://doi.org/10.1103/PhysRevResearch.6.043132
M3 - مقالة
SN - 2643-1564
VL - 6
JO - PHYSICAL REVIEW RESEARCH
JF - PHYSICAL REVIEW RESEARCH
IS - 4
M1 - 043132
ER -