6533b7d6fe1ef96bd12667f9
RESEARCH PRODUCT
Momentum-space structure of surface states in a topological semimetal with a nexus point of Dirac lines
Timo HyartTero T. Heikkiläsubject
PhysicsSurface (mathematics)topological semimetalsDirac linesCondensed Matter - Mesoscale and Nanoscale Physicsta114Dirac (software)Honeycomb (geometry)FOS: Physical sciencesPosition and momentum space02 engineering and technologyType (model theory)021001 nanoscience & nanotechnologyTopology01 natural sciencesSymmetry (physics)Topological defectQuantum mechanics0103 physical sciencesHomogeneous spaceMesoscale and Nanoscale Physics (cond-mat.mes-hall)010306 general physics0210 nano-technologydescription
Three-dimensional topological semimetals come in different variants, either containing Weyl points or Dirac lines. Here we describe a more complicated momentum-space topological defect where several separate Dirac lines connect with each other, forming a momentum-space equivalent of the real-space nexus considered before for helium-3. Close to the nexus the Dirac lines exhibit a transition from type I to type II lines. We consider a general model of stacked honeycomb lattices with the symmetry of Bernal (AB) stacked graphite and show that the structural mirror symmetries in such systems protect the presence of the Dirac lines, and also naturally lead to the formation of the nexus. By the bulk-boundary correspondence of topological media, the presence of Dirac lines lead to the formation of drumhead surface states at the side surfaces of the system. We calculate the surface state spectrum, and especially illustrate the effect of the nexus on these states.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-01-01 | Physical Review B |