1202.2127 (Rahul Nandkishore et al.)

Itinerant half-metal spin-density-wave state on the hexagonal lattice    [PDF]

Rahul Nandkishore, Gia-Wei Chern, Andrey V. Chubukov

We consider electrons on a honeycomb or triangular lattice doped to the
saddle point of the bandstructure. We assume system parameters are such that
spin density wave (SDW) order emerges below a temperature $T_N$ and investigate
the nature of the SDW phase. We argue that at $T < T_N$ the system develops a
uniaxial SDW phase whose ordering pattern breaks $O(3) \times Z_4$ symmetry and
corresponds to an eight site unit cell with non-uniform spin moments on
different sites. This state is a half-metal -- it preserves full original Fermi
surface, but has gapless charged excitations in one spin branch only. It allows
for electrical control of spin currents and is desirable for nano-science.

View original: http://arxiv.org/abs/1202.2127