Certain lattice wave systems in translationally invariant settings have one or more spectral
bands that are strictly flat or independent of momentum in the tight binding approximation …

Conspectus Metal–organic and covalent–organic frameworks (MOFs/COFs) have been
extensively studied for fundamental interests and their promising applications, taking …

Photonic devices rarely provide both elaborate spatial control and sharp spectral control
over an incoming wavefront. In optical metasurfaces, for example, the localized modes of …

We review recent progresses in the study of flat band systems, especially focusing on the
fundamental physics related to the singularity of the flat band's Bloch wave functions. We first …

We show that flat bands can be categorized into two distinct classes, that is, singular and
nonsingular flat bands, by exploiting the singular behavior of their Bloch wave functions in …

The introduction of the concept of topology into condensed matter physics has greatly
deepened our fundamental understanding of transport properties of electrons as well as all …

Two-dimensional covalent organic frameworks (2D-COFs), also referred to as 2D polymer
networks, display unusual electronic-structure characteristics, which can significantly enrich …

Analogies between electronic condensed matter systems and optics attract widespread
attention nowadays, underlying much research in photonics. Prominent examples where …

We report angle resolved photoemission experiments on a newly discovered family of
kagome metals RV 6 Sn 6 (R= Gd, Ho). Intrinsic bulk states and surface states of the …

Flat-band systems have attracted considerable interest in different branches of physics in the
past decades, providing a flexible platform for studying fundamental phenomena associated …