A Comparative Study of 1D Monatomic Fe-chain and 3D Fe-bulk within the Density Functional Theory (DFT)

The structural, electronic and magnetic properties of Fe bulk and the monatomic Fe-nano wire has been theoretically investigated within the full potential linearized augmented plane wave (FP-LAPW) based on density functional theory (DFT). This work is a comparative study of Fe-bulk and the 1D Fe chain. A most commonly adopted GGA approximation is use for electron exchange correlation. In our calculation the property of bulk is predicted to be magnetic metal.Though there is no significant band gap at the Fermi level (EF ) in Fe-wire, whereas the presence of deep valley (Spin up) and a peak(Spin down) at the EF shows the phenomenon of high antisymmetric density of states (DOS). The presence of high antisymmetric DOS may lead to spin polarization at the EF . Also the two anti-symmetric sharp peaks at two different energies give the exchange splitting. The exchange splitting between the degenerated d-states is dispersed and not much effective in the bulk system but the splitting between t2g states is very prominent in Fe-chain which enhanced the magnetic moment.