Related papers: Bilayer Kagome Borophene with Multiple van Hove Si…
The recently discovered family of AV$_3$Sb$_5$ (A: K, Rb Cs) kagome metals possess a unique combination of nontrivial band topology, superconducting ground states, and signatures of electron correlations manifest via competing charge…
We theoretically show that in the presence of conventional or higher order van Hove singularities(VHS), the bare finite momentum pairing, also known as the pair density wave (PDW), susceptibility can be promoted to the same order of the…
We investigate the electronic instabilities in a Kagome lattice with Rashba spin-orbital coupling by the unbiased singular-mode functional renormalization group. At the parent $1/3$-filling, the normal state is a quantum spin Hall system.…
We study theoretically and numerically high density of states for hyperbolic bilayered metamaterials (HMM). It reveals that density response of HMM is reminiscent of Fermi electronic band structure of metal or semiconductors. By the method…
While it is known that the double-layer Bi$_2$Sr$_2$CaCu$_2$O$_{8+y}$ (BSCCO) cuprate superconductor exhibits a one-dimensional (1D) incommensurate superlattice (IS), the effect of IS on the electronic structure remains elusive. Following…
The antiferromagnetic kagome lattice compound FeGe has been revealed to host an emergent charge-density-wave (CDW) state which manifests complex interplay between the spin, charge and lattice degrees of freedom. Here, we present a…
The transition-metal-based kagome metals provide a versatile platform for correlated topological phases hosting various electronic instabilities. While superconductivity is rare in layered kagome compounds, its interplay with nontrivial…
We explore the emergence of phonon-mediated superconductivity in bilayer borophenes by controlled intercalation with elements from the groups of alkali, alkaline-earth, and transition metals, using systematic first-principles and Eliashberg…
Extensive scanning tunnelling microscopy and spectroscopy experiments complemented by first principles and parameterized tight binding calculations provide a clear answer to the existence, origin and robustness of van Hove singularities…
The flattening of single-particle band structures plays an important role in the quest for novel quantum states of matter due to the crucial role of interactions. Recent advances in theory and experiment made it possible to construct and…
In the quest for topology- and correlation-driven quantum states, kagome lattice materials have garnered significant interest for their band structures, featuring flat bands (FBs) from the quantum destructive interference of the electronic…
We observe that H$_3$S has a bcc structure and, with nearest neighbour hopping only, a strong singularity occurs at zero energy. This singularity is accompanied with a highly nested Fermi surface, which is {\it not} conducive to a stable…
Borophene has triggered a surge of interest due to its outstanding properties including mechanical flexibility, polymorphism, and opto-electrical anisotropy. Very recently, a novel semi-hydrogenated borophene, called $\alpha'$-4H, was…
Single-layer carbon, or graphene, demonstrates amazing transport properties, such as the minimum conductivity near $\frac{4e^2}{h}$ independent of shapes and mobility of samples. This indicates there exist some unusual effects due to…
We study a single component (i.e., single valley, spin-polarized) two-dimensional electron gas with $C_{3v}$ symmetry tuned to a Van-Hove (VH) singularity. Generically, there may be either three or six VH points at the Fermi level, related…
Surface Van Hove singularity (SVHS), defined as the surface states near the Fermi level (EF) in low-dimensional systems, triggers exciting physical phenomena distinct from bulk. We herein explore theoretically the potential role of SVHS in…
Two-dimensional (2D) Dirac cone materials exhibit linear energy dispersion at the Fermi level, where the effective masses of carriers are very close to zero and the Fermi velocity is ultrahigh, only 2 ~ 3 orders of magnitude lower than the…
We report an angle-resolved photoemission study of BaFe2As2, a parent compound of iron-based superconductors. Low-energy tunable excitation photons have allowed the first observation of a saddle-point singularity at the Z point, as well as…
Van Hove singularities (vHs) located close to the Fermi level in Kagome superconductors AV3Sb5 (A = K, Rb, Cs) have profound influence on their electronic and transport characteristics. Specifically, magneto-transport and susceptibility…
The energy dispersion of fermions or bosons vanishes in momentum space if destructive quantum interference occurs in a frustrated Kagome lattice with only nearest-neighbour (NN) hopping. A discrete flat band (FB) without any dispersion is…