Year: 2023
Type: article
Abstract: The band structure for a crystal generally consists of connected components in energy-momentum space, known as band complexes. Here, we explore a fundamental aspect regarding the maximal number of bands that can be accommodated in a single band complex. We show that, in principle, a band complex can have no finite upper bound for certain space groups. This means infinitely many bands can entangle together, forming a connected pattern stable against symmetry-preserving perturbations. This is demonstrated by our developed inductive construction procedure, through which a given band complex can always be grown into a larger one by gluing a basic building block to it. As a by-product, we demonstrate the existence of arbitrarily large accordion-type band structures containing ${N}_{C}=4n$ bands, with $n\ensuremath{\in}\mathbb{N}$.
Institutions: Northwest University, Shaanxi Key Laboratory for Theoretical Physics Frontiers, Singapore University of Technology and Design, Beijing University of Chemical Technology, Shandong University, Beijing Institute of Technology, Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4382056961