Regular Article - Solid State and Materials
Topology of contact points in Lieb–kagomé model
Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS, 91405, Orsay, France
Accepted: 2 May 2021
Published online: 28 June 2021
We analyse Lieb–kagomé model, a three-band model with contact points showing particular examples of the merging of Dirac contact points. We prove that eigenstates can be parametrized in a classification surface, which is a hypersurface of a 4-dimension space. This classification surface is a powerful device giving topological properties of the energy band structure; the analysis of its fundamental group proves that all singularities of the band structure can be characterized by four independent winding (integer) numbers. Lieb case separates: its classification surface differs and there is only one winding number.
© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2021