  We investigate the possibility to obtain a thermal diode with functionally
graded Si-Ge alloys. A wire with variable section is considered. After the
introduction of a formula giving the thermal conductivity of the wire as a
function of the species content and of the diameter of the wire, numerical and
analytical results are presented supporting the impracticability to get a
thermal diode with the characteristics here considered. However, the present
study opens the way to further generalisations amenable to give applicative
promising results.
