Electronic structure of erbium disilicide

The calculation of the electronic structure of ideal ${\mathrm{ErSi}}_2$ has been performed using the linear-muffin-tin-orbital method. Tight-binding parameters were then obtained by fitting to the calculated dispersion curves and applied to two nonstoichiometric ${\mathrm{ErSi}}_{1.7}$ structures corresponding to different vacancy orderings along the c crystal axis. Comparison is made with experimental photoemission data and the relative stability of the different phases is discussed as well as the low value of the Schottky barrier at the ${\mathrm{ErSi}}_2$-Si interface.