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

## TL;DR

This paper proposes a new class of half-metallic states called spin-valley half-metals, which can be stabilized in doped spin-density wave insulators, expanding the understanding of half-metallicity beyond strongly correlated systems.

## Contribution

It introduces the concept of spin-valley half-metals in weak-coupling regimes, showing how doping can induce full spin-valley polarization in nested band structures.

## Key findings

- Doping a spin-density wave insulator can stabilize half-metallic states.
- Two types of spin polarization configurations are possible: parallel and antiparallel.
- The spin-valley half-metal exhibits complete polarization with respect to the spin-valley operator.

## 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.