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arXiv · 0712.2439

Electron fractionalization for two-dimensional Dirac fermions

Claudio Chamon·Chang-Yu Hou·Roman Jackiw·Christopher Mudry·So-Young Pi·Gordon Semenoff
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Abstract

Fermion-number fractionalization without breaking of time-reversal symmetry was recently demonstrated for a field theory in $(2+1)$-dimensional space and time that describes the couplings between massive Dirac fermions, a complex-valued Higgs field carrying an axial gauge charge of 2, and a U(1) axial gauge field. Charge fractionalization occurs whenever the Higgs field either supports vortices by itself, or when these vortices are accompanied by half-vortices in the axial gauge field. The fractional charge is computed by three different techniques. A formula for the fractional charge is given as a function of a parameter in the Dirac Hamiltonian that breaks the spectral energy-reflection symmetry. In the presence of a charge $\pm1$ vortex in the Higgs field only, the fractional charge varies continuously and thus can take irrational values. The simultaneous presence of a half-vortex in the axial gauge field and a charge $\pm1$ vortex in the Higgs field re-rationalizes the fractional charge to the value 1/2.

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Claudio Chamon, Chang-Yu Hou, Roman Jackiw, Christopher Mudry, So-Young Pi, Gordon Semenoff. 2007-12-14. Electron fractionalization for two-dimensional Dirac fermions. https://doi.org/10.1103/physrevb.77.235431

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