Spin-valley half-metal as a prospective material for spin-valley-tronics

Abstract

Half-metallicity (full spin polarization of the Fermi surface) usually occurs in strongly correlated electron systems. We demonstrate that doping a spin-density wave insulator in the weak-coupling regime may also stabilize half-metallic states. The undoped spin-density wave is formed by four nested bands [i.e., each band is characterized by charge (electron/hole) and spin (up/down) labels]. Of these four bands only two accumulate the doped carriers, forming a half-metallic two-valley Fermi surface. Depending on parameters, the spin polarizations of the electron-like and hole-like valleys may be (i) parallel or (ii) antiparallel. The Fermi surface of (i) is fully spin-polarized (similar to usual half-metals). Case (ii), referred to as "a spin-valley half-metal", corresponds to complete polarization with respect to the spin-valley operator. The properties of these states are discussed.

6 pages, 2 eps figures

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• Competition of spatially inhomogeneous states in antiferromagnetic Hubbard model
• Half-metal and other fractional metal phases in doped AB bilayer graphene
• Dynamical spin susceptibility of spin-valley half-metal
• Magic radius of AA bilayer graphene quantum dot
• Ordering in SU(4)-symmetric model of AA bilayer graphene
• Spin-density wave state in simple hexagonal graphite
• Nesting-driven ferromagnetism of itinerant electrons