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

作者：Nandkishore Rahul^*; Chern Gia Wei; Chubukov Andrey V

来源：Physical Review Letters, 2012, 108(22): 227204.

DOI：10.1103/PhysRevLett.108.227204

We consider electrons on a honeycomb or triangular lattice doped to the saddle point of the band structure. We assume the 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) X Z(4) symmetry and corresponds to an eight-site unit cell with nonuniform spin moments on different sites. This state is a half-metal-it preserves the 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 nanoscience.

• 出版日期2012-5-30