The story of Dirac masses and their topological defects in graphene - like systems

Date

Dec 18, 2012

Time

4:40 PM - 6:10 PM

Speaker

Prof. Dr. Igor Herbut

Affiliation

Simon Fraser University/MPI - PKS

Series

TUD Physikalisches Kolloquium

Language

en

Main Topic

Physik

Other Topics

Physik

Description

I will discuss the spectrum of quasiparticles in the Dirac systems like graphene, in the presence of domain walls, vo rtices, or hedgehogs of superconducting and/or insulating order parameters. These orders formally appear as the mass terms in the Dirac equation, and their topological defects have been known to carry non - trivial quantum numbers such as charge and spin. In the talk I will discuss their additional internal degree of freedom: irrespectively of the nature of orders that support the defect, an extra mass order parameter is found to spontaneously emerge in their core. The particle - hole symmetry restricts the def ects to carry the quantum numbers of a single effective isospin 1/2, quite independently of the values of their electric charge or true spin. Some examples of this new degree of freedom in graphene and on surfaces of topological insulators will be given, a nd connections to the mathematics of Clifford algebras will be briefly mentioned.

Last modified: Dec 18, 2012, 9:04:31 AM