相关论文: Observation of Gapless Dirac Surface States in ZrG…
Dirac semimetals (DSMs) are three dimensional analogue to graphene with symmety enforced bulk Dirac nodes. Among various DSMs, ZrSiS has been attracting more interests recently, due to its three dimensional Dirac nodal line protected by the…
Unveiling new topological phases of matter is one of the current objectives in condensed matter physics. Recent experimental discoveries of Dirac and Weyl semimetals prompt to search for other exotic phases of matter. Here we present a…
Topological Dirac semimetals with accidental band touching between conduction and valence bands protected by time reversal and inversion symmetry are at the frontier of modern condensed matter research. Theoretically one can get Weyl and/or…
Topologically protected fermionic quasiparticles occur in metals with band degeneracy as a consequence of band structure topology. Here we unveil topological semimetal and metal phases in a variety of non-symmorphic collinear…
The search of new topological phases of matter is one of the new directions in condensed matter physics. Recent experimental realizations of Dirac semimetal phases pave the way to look for other exotic phases of matter in real materials.…
We have performed angle-resolved photoemission spectroscopy (ARPES) on layered ternary compounds ZrGeXc (Xc = S, Se, and Te) with square Ge lattices. ARPES measurements with bulk-sensitive soft-x-ray photons revealed a quasi-two-dimensional…
The three-dimensional topological semimetals represent a new quantum state of matter. Distinct from the surface state in the topological insulators that exhibits linear dispersion in two-dimensional momentum plane, the three-dimensional…
Topological semimetals, such as the Weyl and Dirac semimetals, represent one of the most active research fields in modern condensed matter physics. The peculiar physical properties of these systems mainly originate from their underlying…
Topological nodal-line semimetals represent a unique class of materials with intriguing electronic structures and rich of symmetries, hosting electronic states with nontrivial topological properties. Among these, ZrAs$_2$ stands out,…
The three dimensional (3D) Dirac semimetal, which has been predicted theoretically, is a new electronic state of matter. It can be viewed as 3D generalization of graphene, with a unique electronic structure in which conduction and valence…
We report a new, cleavable, strong-topological-metal, Zr2Te2P, which has the same tetradymite-type crystal structure as the topological insulator Bi2Te2Se. Instead of being a semiconductor, however, Zr2Te2P is metallic with a pseudogap…
Quantum materials having Dirac fermions in conjunction with superconductivity is believed to be the candidate materials to realize exotic physics as well as advanced technology. Angle resolved photoemission spectroscopy (ARPES), a direct…
Motivated by recent experiments probing anomalous surface states of Dirac semimetals (DSMs) Na$_3$Bi and Cd$_3$As$_2$, we raise the question posed in the title. We find that, in marked contrast to Weyl semimetals, the gapless surface states…
Ternary transition-metal germanide superconductors with nonsymmorphic symmetries offer promising platforms for symmetry-protected topological phases. In this work, we investigate ZrIrGe, which crystallizes in the nonsymmorphic TiNiSi-type…
We have performed angle-resolved photoemission spectroscopy (ARPES) on the (111) surface of the topological crystalline insulator SnTe. Distinct from a pair of Dirac-cone surface states across the X_bar point of the surface Brillouin zone…
Among the quantum materials that gained interest recently are the topological Dirac/Weyl semimetals, where conduction and valence bands touch at points in reciprocal (k)-space, and the Dirac nodal-line semimetals, where these bands touch…
Nodal line semimetals feature topologically protected band crossings between the bulk valence and conduction bands that extend along a finite dimension in the form of a line or a loop. While ZrSiS and similar materials have attracted…
Weyl and Dirac semimetals are three dimensional phases of matter with gapless electronic excitations that are protected by topology and symmetry. As three dimensional analogs of graphene, they have generated much recent interest. Deep…
In a topological insulator, it is the electrons on the surface or edge that carry the signature of topology. Recently, a novel topological state has been proposed in metals or semimetals (gapless) whose band-structure is similar to that of…
We reconsider the problem of surface states spectrum in type One Dirac metals. We find that the surface states, despite being gapped, always form branches terminating at Dirac points. Furthermore, we consider evolution of the surface states…