Related papers: Three-dimensional higher-spin Dirac and Weyl dispe…
In a Dirac semimetal, the conduction and valence bands contact only at discrete (Dirac) points in the Brillouin zone (BZ) and disperse linearly in all directions around these critical points. Including spin, the low energy effective theory…
Relativistic massless Weyl and Dirac fermions exhibit the isotropic and linear dispersion relations to preserve the Poincar\'{e} symmetry, the most fundamental symmetry in high energy physics. In solids, the counterparts of the Poincar\'{e}…
While "Dirac cone" dispersions can only be meaningfully defined in two dimensional (2D) systems, the notion of a Dirac point can be extended to three dimensional (3D) classical wave systems. We show that a simple cubic photonic crystal…
A single Dirac cone on the surface is the hallmark of three-dimensional (3D) topological insulators, where the double degeneracy at the Dirac point is protected by time-reversal symmetry and the spin-splitting away from the point is…
Recently, the gapless Dirac/Weyl nodal semimetals with linear dispersion and topologically protected modes degeneracy are rapidly growing frontiers of topological physics. Especially, type-I, type-II, and critical type-III nodal semimetals…
The extraordinary electronic properties of Dirac materials, the two-dimensional partners of Weyl semimetals, arise from the linear crossings in their band structure. When the dispersion around the Dirac points is tilted, the emergence of…
Theoretical evidence of the existence of six inequivalent and six threefold degenerate pairs of Dirac cones in the low-spectrum diagram of monolayered hexagonal CrB4 is provided. The four d-electrons of the Cr atom are yielded to the B…
We introduce the concept of 3D Dirac (Weyl) superconductors (SC), which have protected bulk four(two)-fold nodal points and surface Andreev arcs at zero energy. We provide a sufficient criterion for realizing them in centrosymmetric SCs…
The three-dimensional (3D) Dirac point, where two Weyl points overlap in momentum space, is usually unstable and hard to realize. Here we show, based on the first-principles calculations and effective model analysis, that crystalline…
When the spin-orbit coupling (SOC) is absent, almost all the proposed half-metals with the twofold degenerate nodal points at the K (or K') in two-dimensional (2D) materials are misclassified as "Dirac half-metals" owing to the way graphene…
Topological semimetals, representing a new topological phase that lacks a full bandgap in bulk states and exhibiting nontrivial topological orders, recently have been extended to photonic systems, predominantly in photonic crystals and to a…
We show that a class of compounds with $I$4/$mcm$ crystalline symmetry hosts three-dimensional semi-Dirac fermions. Unlike the known two-dimensional semi-Dirac points, the degeneracy of these three-dimensional semi-Dirac points is not…
We investigate the finite-frequency optical response of systems described at low energies by Dirac-Weyl Hamiltonians with higher pseudospin $\mathcal{S}$ values. In particular, we examine the situation where a tilting term is applied in the…
We investigate a generalized two-dimensional Weyl Hamiltonian, which may describe the low-energy properties of mechanically deformed graphene and of the organic compound alpha-(BEDT-TTF)_2I_3 under pressure. The associated dispersion has…
Spin-1 Weyl point is formed by three bands touching at a single point in the three dimensional (3D) momentum space, with two of which show cone-like dispersion while the third band is flat. Such a triply degenerate point carries higher…
High-order topological charge is of intensive interest in the field of topological matters. In real materials, cubic Dirac point is rare and the chiral charge of one Weyl point (WP) has never be found to exceed |C| = 3 for spin- 1/2…
We report the observation by angle-resolved photoemission spectroscopy measurements of a highly anisotropic Dirac-cone structure in high quality SrMnBi2 crystals. We reveal a well-defined sharp quasi-particle, linearly dispersive with…
Looking for new materials with Dirac points has been a fascinating subject of research. Here we report the growth, crystal structure, and band structure of HfGe0.92Te single crystals, featuring three different types of Dirac points.…
In monolayer transition metal dichalcogenides, tightly bound excitons have been discovered with a valley pseudospin that can be optically addressed through polarization selection rules. Here, we show that this valley pseudospin is strongly…
Electron systems that possess light-like dispersion relations or the conical Dirac spectrum, such as graphene and bismuth, have recently been shown to harbor unusual collective states in high magnetic fields. Such states are possible…