1202.3983 (Xiao-Liang Qi)

A new class of $(2+1)$-d topological superconductor with $\mathbb{Z}_8$
topological classification    [PDF]

Xiao-Liang Qi

The classification of topological states of matter depends on spatial
dimension and symmetry class. For non-interacting topological insulators and
superconductors the topological classification is obtained systematically and
nontrivial topological insulators are classified by either integer or $Z_2$.
The classification of interacting topological states of matter is much more
complicated and only special cases are understood. In this paper we study a new
class of topological superconductors in $(2+1)$ dimensions which has
time-reversal symmetry and a $\mathbb{Z}_2$ spin conservation symmetry. We
demonstrate that the superconductors in this class is classified by
$\mathbb{Z}_8$ when electron interaction is considered, while the
classification is $\mathbb{Z}$ without interaction.

View original: http://arxiv.org/abs/1202.3983