Unusual electronic transport properties of the intermetallic compounds RuAl$_{2 }$and RuGa$_{2}$*

Semiconductor-like electrical transport has been reported for the title compounds RuAl$_{2}$ and RuGa$_{2.}$ Band structure calculations performed on these compounds suggest band gap opening or minimum density of states in the vicinity of Fermi level due to the hybridization of d- and sp-bands. The observed transport properties are rather unusual and attributed to band hybridization. Our primary objective is to study these transport properties in detail. We have prepared single phase compounds by a combination of arc melting and subsequent annealing at 950$^{\circ}$C - 750$^{\circ}$C. Measurements of the electrical resistivity, thermopower and Hall coefficient are being carried out below room temperature. The results of these experiments will be presented and discussed