1202.4163 (Guang-Yao Huang et al.)

Edge states and topological orders in the spin liquid phases of star
lattice    [PDF]

Guang-Yao Huang, Shi-Dong Liang, Dao-Xin Yao

A group of novel materials can be mapped to the star lattice, which exhibits
some novel physical properties. We give the bulk-edge correspondence theory of
the star lattice and study the edge states and their topological orders in
different spin liquid phases. The bulk and edge-state energy structures and
Chern number depend on the spin liquid phases and hopping parameters because
the local spontaneous magnetic flux in the spin liquid phase breaks the time
reversal and space inversion symmetries. We give the characteristics of bulk
and edge energy structures and their corresponding Chern numbers in the
uniform, nematic and chiral spin liquids. In particular, we obtain analytically
the phase diagram of the topological orders for the chiral spin liquid states
SL[\phi,\phi,-2\phi], where \phi is the magnetic flux in two triangles and a
dodecagon in the unit cell. Moreover, we find the topological invariance for
the spin liquid phases, SL[\phi_{1},\phi_{2},-(\phi_{1}+\phi_{2})] and
SL[\phi_{2},\phi_{1},-(\phi_{1}+\phi_{2})]. The results reveal the relationship
between the energy-band and edge-state structures and their topological orders
of the star lattice.

View original: http://arxiv.org/abs/1202.4163