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A milestone in graphene research was the 2005 discovery of an integer quantum Hall effect. In contrast to its manifestation in conventional two-dimensional (2D) electron systems, such as in semiconductor heterostructures, the graphene quantum Hall effect reflects the "ultra-relativistic" character of the underlying carriers, via a particular sequence of plateaus in the transverse Hall resistance. In view of the fractional cousin of the integer quantum Hall effect in 2D electron systems, one may thus naturally ask the question about a fractional quantum Hall effect in graphene. Does it also reflect the ultra-relativistic character of the charge carriers? To what extent is it different from the fractional quantum Hall effect in (non-relativistic) semiconductor heterostructures? Many of these questions remain open from an experimental point of view, although some fractional states have recently been observed in transport and spectroscopic measurements. This talk aims at a theoretical perspective on the fractional quantum Hall effect in graphene, namely in view of its multi-component character due to the fourfold spin-valley degeneracy, which gives rise to an internal SU(4) symmetry and that is approximately respected by the underlying electron-electron interactions. This theoretical perspective will be confronted with recent experimental advances.

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Dr. Mark Oliver Goerbig, Universite Paris Sud
Seminarraum Theoretische Physik
Contact: not specified