Half-integer filling-factor states in quantum dots.

The emergence of half-integer filling-factor states, such as upsilon=5/2 and 7/2, is found in quantum dots by using numerical many-electron methods. These states have interesting similarities and differences with their counterstates found in the two-dimensional electron gas. The upsilon=1/2 states in quantum dots are shown to have high overlaps with the composite fermion states. The lower overlap of the Pfaffian state indicates that electrons might not be paired in quantum dot geometry. The predicted upsilon=5/2 state has a high spin polarization, which may have an impact on the spin transport through quantum dot devices.