  Density Functional Theory (DFT) has become the quasi-standard for ab-initio
simulations for a wide range of applications. While the intrinsic cubic scaling
of DFT was for a long time limiting the accessible system size to some hundred
atoms, the recent progress with respect to linear scaling DFT methods has
allowed to tackle problems that are larger by many orders of magnitudes.
However, as these linear scaling methods were developed for insulators, they
cannot, in general, be straightforwardly applied to metals, as a finite
temperature is needed to ensure locality of the density matrix. In this paper
we show that, once finite electronic temperature is employed, the linear
scaling version of the BigDFT code is able to exploit this locality to provide
a computational treatment that scales linearly with respect to the number of
atoms of a metallic system. We provide prototype examples based on bulk
Tungsten, which plays a key role in finding safe and long-lasting materials for
Fusion Reactors. We believe that such an approach might help in opening the
path towards novel approaches for investigating the electronic structure of
such materials, in particular when large supercells are required.

Materials Science