Related papers: Ideal type-II Weyl points in topological circuits
We present a study of "nodal semimetal" phases, in which non-degenerate conduction and valence bands touch at points (the "Weyl semimetal") or lines (the "line node semimetal") in three-dimensional momentum space. We discuss a general…
Weyl photons appear when two three-dimensional photonic bands with linear dispersion are degenerate at a single momentum point, labeled as Weyl point. These points have remarkable properties such as being robust topological monopoles of…
According to a widely-held paradigm, a pair of Weyl points with opposite chirality mutually annihilate when brought together. In contrast, we show that such a process is strictly forbidden for Weyl points related by a mirror symmetry,…
By means of $ab \ initio$ band structure methods and model Hamiltonians we investigate the electronic, spin and topological properties of four monopnictides crystallizing in body centered tetragonal structure. We show that the Weyl bands…
Type-II Dirac points (DPs), which occur at the intersection of strongly tilted and touching energy bands, exhibit many intriguing physical phenomena fundamentally different from the non-tilted type-I counterparts. Over the past decade,…
We propose a realization of the Weyl semimetal phase that is invariant under time reversal and occurs due to broken inversion symmetry. We consider both a simple superlattice model and a more realistic tight-binding model describing an…
The topological metal states in electronic systems have been extensively studied, but topological phonons were explored only in few examples so far. Here, we expose for the first time that the topological nodal gimbal phonons, type-I and…
The hypothetical Weyl particles in high-energy physics have been discovered in three-dimensional crystals as collective quasiparticle excitations near two-fold degenerate Weyl points. Such momentum-space Weyl particles carry quantized…
Weyl nodes are topological objects in three-dimensional metals. Their topological property can be revealed by studying the high-field transport properties of a Weyl semimetal. While the energy of the lowest Landau band (LLB) of a…
Using first--principles density functional calculations, we systematically investigate electronic structures and topological properties of InNbX2 (X=S, Se). In the absence of spin--orbit coupling (SOC), both compounds show nodal lines…
Three-dimensional topological Weyl semimetals can generally support a zero-dimensional Weyl point characterized by a quantized Chern number or a one-dimensional Weyl nodal ring (or line) characterized by a quantized Berry phase in the…
Weyl fermions1 do not appear in nature as elementary particles, but they are now found to exist as nodal points in the band structure of electronic and classical wave crystals. Novel phenomena such as Fermi arcs and chiral anomaly have…
Recently three dimensional topological quantum materials with gapless energy spectra have attracted considerable interests in many branches of physics. Besides the celebrated example, Dirac and Weyl points which possess gapless point…
Quite recently a novel variety of unconventional fourfold linear band degeneracy points has been discovered in certain condensed-matter systems. Contrary to the standard 3-D Dirac monopoles, these quadruple points referred to as the…
Double Weyl nodes are topologically protected band crossing points which carry chiral charge $\pm2$. They are stabilized by $C_4$ point group symmetry and are predicted to occur in $\mathrm{SrSi_2}$ or $\mathrm{HgCr_{2}Se_{4}}$. We study…
Electronic flat bands have localized Wannier-like orbitals as zero modes. In the Lieb or the kagome models, the localized orbitals satisfy a topological condition that entails two non-contractible loop eigenstates along $x/y$-axis in real…
Weyl points are often believed to appear in pairs with opposite chirality. In this work, we show by first-principles calculations and symmetry analysis that single Weyl phonons with linear dispersion and double Weyl phonons with quadratic…
Topological materials have been a main focus of studies in the past decade due to their protected properties that can be exploited for the fabrication of new devices. Among them, Weyl semimetals are a class of topological semimetals with…
We present a theoretical model to study the nonlinear optical response of materials with a low-energy spectrum characterised by strongly tilted, type-II, Weyl cones in two dimensions, which we call 2D Weyl materials. Our findings reveal…
Weyl semimetals and higher-order topological insulators represent two fundamental yet distinct classes of topological matter. While both have been extensively studied in classical-wave systems, their coexistence and controllable transition…