Upcoming Events

Magneto-electric Effects in Bilayer Graphene

June 25, 2014 1:30PM to 2:30PM
Presenter 
Ulrich Zuelicke, Victory University, New Zealand
Location 
Building 241
Type 
Seminar
This Materials Science Division Seminar will take place in the new Energy Sciences Building, 241 ESB, Rm. A323. 

Abstract:
Bilayer graphene is a carbon nanomaterial consisting of two single-layer sheets of graphite. The mobile charge carriers in this conductor turn out to be pseudospin-carrying chiral fermions having a finite band mass but zero rest energy. Our study shows that these exotic particles experience a previously unknown type of electromagnetism in which electric and magnetic fields are virtually indistinguishable: every coupling of an electron's degrees of freedom to a magnetic field is matched by an analogous coupling of the same degrees of freedom to an electric field.

This unusual duality of matter-field interactions enables novel ways to create and manipulate real-spin and layer-index-related pseudo-spin polarizations in bilayer graphene via external fields. The same mechanism also gives rise to a magneto-electric response that is normally seen in band insulators with broken inversion and time-reversal symmetries. In contrast to such systems, the magneto-electric coupling in bilayer graphene is determined by a tunable electronic degree of freedom, namely the valley isospin density, and can therefore be manipulated experimentally.