Correlation effects in the small gap semiconductor FeGa3

We report investigations of the effect of electron doping in FeGa3 via electric resistivity, specific heat and magnetic susceptibility measurements in single crystals. FeGa3 is a non-magnetic small gap semiconductor (Δ ∼ 0.3-0.4 eV). Low concentration of Co in FeGa3 induces a crossover to a metallic-like behavior, also creating weakly coupled local moments. Electronic specific heat and resistivity suggest a mass enhancement of charge carriers. Thus, the low carrier density metal formed by doping FeGa3 presents some physical properties that resemble heavy fermion metals.