Topological band insulators and (semi-) metals can arise out of atomic when the hopping strength between electrons increases. Such topological phases are separated from insulator by a bulk gap closing. In this work, we show that in many (magnetic) space groups, crystals with certain Wyckoff positions orbitals being occupied must be semimetal or limit, e.g. is infinite weak but not vanishing, wh...

The notion of higher-order topological insulators has endowed materials with states beyond the first order. Particularly, a three-dimensional (3D) insulator can host topologically protected 1D hinge states, referred to as second-order insulator, or 0D corner third-order insulator. Similarly, 3D semimetal be envisaged if it hosts on hinges. Here we report realization Weyl in 3D-printed acoustic ...

We study the band topology of superconducting nodal-line semimetal (SC-NLSM) protected by inversion symmetry with and without spin-orbital coupling. Without coupling, both $s$-wave SC-NLSM chiral $p$-wave are topologically nontrivial can be described nonzero winding number. Based on Wilson loop method, we verify that they fragile topological superconductors, namely, their topologies moved off c...

A feasible strategy to realize the Majorana fermions is searching for a simple compound with both bulk superconductivity and Dirac surface states. In this paper, we performed calculations of electronic band structure, Fermi states, as well measured resistivity, magnetization, specific heat TlSb CsCl-type structure. The structure show that semimetal when spin-orbit coupling taken into account. M...

As a new type of quantum state matter hosting low energy relativistic quasiparticles, Weyl semimetals (WSMs) have attracted significant attention for scientific community and potential device applications. In this study, we present comprehensive investigation the structural, magnetic, transport properties noncentrosymmetric R AlSi ( = Sm, Ce), which been predicted to be magnetic WSM candidates....

A multifold Hopf semimetal is a topological point node possessing an anisotropy in the internal electronic structure, e.g., dipole structure of Berry curvature. In this paper, unique features threefold semimetals terms optical conductivity are theoretically investigated with minimal theoretical model by using linear response theory for linearly polarized photon. The frequency spectrum shows ani...