Theoretical study of field emission currents from W(001) surface

We calculated the field emission of the W(001) surface based on a local density functional method. In this method, the electronic structure and the potential under an external electric field are calculated self-consistently using the pseudopotential method. The method is easy to implement and requires minimal computation time beyond that of a standard density functional calculation, while at the same time fully compatible with the density functional formalism. Results such as the enhancement factors are in good agreement with experiments and the effect of the surface reconstruction and the choice of exchange-correlation functionals on the field emission current will be discussed.