Abstract
We propose a two-dimensional time-reversal invariant system of essentially noninteracting electrons on a square lattice that exhibits configurations with fractional charges . These are vortexlike topological defects in the dimerization order parameter describing spatial modulation in the electron hopping amplitudes. Charge fractionalization is established by a simple counting argument, analytical calculation within the effective low-energy theory, and by an exact numerical diagonalization of the lattice Hamiltonian. We comment on the exchange statistics of fractional charges and possible realizations of the system.
- Received 11 June 2007
DOI:https://doi.org/10.1103/PhysRevB.77.033104
©2008 American Physical Society