Abstract:
The spin ordering of the observed quantized
Hall plateau with sigma
xy
=5/2 e
2
/h has become a pressing issue due to its pertinence to the identification of this state of matter as a potential
platform for topological quantum computation. Experimental and
numerical
studies have not, thus far, settled this issue, although
they are consistent with a fully spin-polarized Moore-Read Pfaffian ground
state. In this talk, I will present theoretical and numerical evidence that the ground state at this fraction is
polarized even if the Zeeman energy vanishes [1].
I will construct an effective Ginsburg-Landau theory by drawing analogies
with the spin physics at nu=1, and the physics of triplet
ferromagnetic superconductors. The novel features of a proposed phase
diagram include the existence of partially polarized paired states, as well as novel topological spin textures as elementary
excitations. I will discuss the experimental significance of our work.
Refs.
[1] I. Dimov, B. Halperin, C. Nayak, arXiv:0710.1921, accepted to Phys. Rev. Lett..