### Session H30: Electronic Properties of Graphene and Related Structures II

8:00 AM–11:00 AM, Tuesday, March 11, 2008
Morial Convention Center Room: 222

Chair: Giovanni Cantele, Istituto Nazionale per la Fisica della Materia

Abstract ID: BAPS.2008.MAR.H30.9

### Abstract: H30.00009 : Irrational vs. rational charge and statistics in graphene-like system

9:36 AM–9:48 AM

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#### Authors:

Chang-Yu Hou
(Department of Physics, Boston University)

Claudio Chamon
(Department of Physics, Boston University)

Roman Jackiw
(Department of Physics, Massachusetts Institute of Technology)

Christopher Mudry
(Condensed matter theory group, Paul Scherrer Institut, Switzerland)

So-Young Pi
(Physics Department, Boston University)

Andreas P. Schnyder
(Department of Physics, University of California, Santa Barbara)

Electron fractionalization is intimately related to topology. In one-dimensional systems, fractionally charged states exist at domain walls between degenerate vacua. In two-dimensional systems, fractionalization exists in quantum Hall fluids, where time-reversal symmetry is broken by a large external magnetic field. Recently, there has been a tremendous effort in the search for examples of fractionalization in two-dimensional systems with time-reversal symmetry. We will show that quasiparticle excitations with irrational charge and irrational exchange statistics exist in tight-biding systems, such as graphene-like structure, described, in the continuum approximation, by the Dirac equation in (2+1)-dimensional space and time. These excitations can be deconfined at zero temperature, but when they are, the charge re-rationalizes to the value 1/2 and the exchange statistics to that of quartons'' (half-semions).

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.MAR.H30.9