Topological semimetals and insulators in three-dimensional honeycomb materials

Datum

28.05.2018

Zeit

14:30 - 15:30

Sprecher

Dennis Wawrzik

Zugehörigkeit

Universität zu Köln

Sprache

en

Hauptthema

Materialien

Andere Themen

Materialien, Physik

Host

Grit Rötzer

Beschreibung

The two-dimensional honeycomb lattice realized in e.g. graphene is well known for its unusual properties. In the electronic band structure Dirac cones with a linear energy dispersion can be found and the presence of spin-orbit coupling gives rise to a topological insulator. The investigation of a family of three-dimensional generalizations of the honeycomb lattice also reveals semimetals in general. Here conduction and valence band do not touch at a single point in k-space but along a line. These Dirac nodal lines appear in varying numbers and mutual geometries, depending on the underlying lattice structure, and are accompanied by topologically protected “drumhead” surface states. In the bulk, these nodal line systems exhibit Landau level quantization and flat bands upon applying a magnetic field. In the presence of spin-orbit coupling, these topological semimetals are found to generically form (strong) topological insulators. .

Links

• Seminars at the IFW

Letztmalig verändert: 28.05.2018, 09:56:56