Half-Metallic Ferromagnetism Induced by Dynamic Electron Correlations in VAs

The electronic structure of the VAs compound in the zinc-blende structure is investigated using a combined density-functional and dynamical mean-field theory approach. Contrary to predictions of a ferromagnetic semiconducting ground state obtained by density-functional calculations, dynamical correlations induce a closing of the gap and produce a half-metallic ferromagnetic state. These results emphasize the importance of dynamic correlations in materials suitable for spintronics.

Figure 1

Schematic representation of the $p\mathrm{\text{−}}d$ hybridization and bonding-antibonding splitting in VAs.

Figure 2

DOS of VAs within the GGA (dashed blue line) and $\mathrm{GGA}+\mathrm{DMFT}$ (solid red line) for a temperature of $T=200\mathrm{K}$, $U=2\mathrm{eV}$, and $J=0.9\mathrm{eV}$. Inset: Focus around $E_F$ showing the semiconducting gap within the GGA. To illustrate the minority-spin NQP states, a 10 times larger scale for the spin-down channel is used.

Figure 3

Energy dependence of real and imaginary parts of the self-energy ${\Sigma }_{\sigma }(E)$ for the $t_{2g}$ orbitals.

Figure 4

Energy dependence of real and imaginary parts of the self-energy ${\Sigma }_{\sigma }(E)$ for the $e_g$ orbitals.