Dirac Fermions in Graphene and Topological Insulators
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  • Dirac Fermions in Graphene and Topological Insulators

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Physics seminar, 02 November Wednesday, 14:40, FASS G022

Speaker: Prof. Dr. Bjoern Trauzettel

From: Institut fuer Theoretische Physik und Astrophysik Universitaet Wuerzburg, Germany


Dirac Fermions in Graphene and Topological Insulators

Abstract

The carbon atoms in graphene (Nobel Prize in Physics 2010) form a
honeycomb lattice which gives rise to many of the peculiar physical
properties of this fascinating material. Due to the interaction of the
electrons with the lattice potential, their low energy properties are
described by the dispersion relation of mass-less Dirac fermions. We
will discuss interesting physical phenomena of Dirac fermions in
graphene such as Klein tunneling, transport through evanescent modes,
and specular Andreev reflection at the boundary to a superconductor.

Furthermore, we will address another (in some sense even richer)
condensed matter system that shows Dirac fermion physics: Topological
insulators (TIs) behave like usual insulators in the bulk but like
metals at the boundaries. This property gives rise to Dirac fermions at
the edge of a TI. In nature, TIs have been first realized in HgTe/CdTe
quantum wells (in 2D) and later on also in 3D in BiSb, BiSe, as well as
BiTe crystals. We will discuss interesting physical properties of 2D and
3D TIs where spin and charge properties are ultimately linked to each other.