Itinerant Half-Metal Spin-Density-Wave State on the Hexagonal Lattice

Rahul Nandkishore, Gia-Wei Chern, Andrey V. Chubukov
2012 Physical Review Letters  
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
more » ... 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.
doi:10.1103/physrevlett.108.227204 pmid:23003647 fatcat:wrcws27gjreqlbfjvhxgnq3j4u