All-electron and pseudopotential study of the spin-polarization of the V„001... surface: LDA versus GGA
نویسندگان
چکیده
The spin-polarization at the V~001! surface has been studied by using different local @local spin-density approximation ~LSDA!# and semilocal @generalized gradient approximation ~GGA#! approximations to the exchange-correlation potential of DFT within two ab initio methods: the all-electron tight-binding linear muffin-tin orbital atomic-sphere approximation and the pseudopotential linear combination of atomic orbitals code SIESTA ~Spanish initiative for electronic simulations with thousands of atoms!. A comparative analysis is performed first for the bulk and then for a N-layer V~001! film (7<N<15). The LSDA approximation leads to a nonmagnetic V~001! surface with both theoretical models in agreement ~disagreement! with magnetooptical Kerr ~electron-capture spectroscopy! experiments. The GGA within the pseudopotential method needs thicker slabs than the LSDA to yield zero moment at the central layer, giving a high surface magnetization ~1.70 Bohr magnetons!, in contrast with the nonmagnetic solution obtained by means of the all-electron code.
منابع مشابه
Breakdown of the pseudopotential approximation for magnetic systems: Predicting magnetic quenching at the V„001... surface with spin-dependent pseudopotentials
Both experimentally @R.L. Fink et al., Phys. Rev. B 41, 10 175 ~1990!# and using all-electron densityfunctional theory ~DFT! methods, the V~001! surface exhibits little or no magnetization. Very recently, independent pseudopotential DFT calculations demonstrated the breakdown of the pseudopotential approximation, showing large magnetic moments at the surface of a V~001! slab. Here we demonstrat...
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