Electronic structure methods Siesta

The energy and electronic structure calculations were carried out in the framework of the DFT method implemented with the SIESTA package [3,4]. Preliminary studies of the adsorption systems and the bonding analysis were achieved using the YAeHMOP program [5], which is based on the semiempirical... 

For completeness we have also calculated with the Siesta code and with the TB-LMTO GGA method the electronic structure and the magnetization for a free standing Fe monolayer. The magnetic moments found with the SZSP and DZSP basis sets are 3.19 fis and 3.23 hb respectively, in good agreement with the TB-LMTO result (3.15 /ub). This corresponds to an enhancement of about 0.15 hb with respect to the (100) surface, due to the loss of coordination. 

The relaxation of the structure in the KMC-DR method was done using an approach based on the density functional theory and linear combination of atomic orbitals implemented in the Siesta code [97]. The minimum basis set of localized numerical orbitals of Sankey type [98] was used for all atoms except silicon atoms near the interface, for which polarization functions were added to improve the description of the SiOx layer. The core electrons were replaced with norm-conserving Troullier-Martins pseudopotentials [99] (Zr atoms also include 4p electrons in the valence shell). Calculations were done in the local density approximation (LDA) of DFT. The grid in the real space for the calculation of matrix elements has an equivalent cutoff energy of 60 Ry. The standard diagonalization scheme with Pulay mixing was used to get a self-consistent solution. In the framework of the KMC-DR method, it is not necessary to perform an accurate optimization of the structure, since structure relaxation is performed many times. 

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