Hopf Semimetals

Autor: Parasar, Bhandaru Phani, Shenoy, Vijay B.
Rok vydání: 2023
Předmět:
Druh dokumentu: Working Paper
Popis: We construct two-band topological semimetals in four dimensions using the unstable homotopy of maps from the three-torus $T^3$ (Brillouin zone of a 3D crystal) to the two-sphere $S^2$. Dubbed ``Hopf semimetals'', these gapless phases generically host nodal lines, with a surface enclosing such a nodal line in the four-dimensional Brillouin zone carrying a Hopf flux. These semimetals show a unique class of surface states: while some three-dimensional surfaces host gapless Fermi-arc states {\em and} drumhead states, other surfaces have gapless Fermi surfaces. Gapless two-dimensional corner states are also present at the intersection of three-dimensional surfaces.
Comment: 5 pages, 4 figures + Supplemental Material (4 pages, 2 figures)
Databáze: arXiv