Single crystals of the perovskite-type

{3 d}^{1}

metallic alloy system

{Ca}_{1 - x} {Sr}_{x} {VO}_{3}

were synthesized in order to investigate metallic properties near the Mott transition. The substitution of a

{Ca}^{2 +}

ion for a

{Sr}^{2 +}

ion reduces the bandwidth

W

due to a buckling of the V-O-V bond angle from

\sim 180 °

for

{SrVO}_{3}

\sim 160 °

for

{CaVO}_{3} .

Thus, the value of

W

can be systematically controlled without changing the number of electrons making

{Ca}_{1 - x} {Sr}_{x} {VO}_{3} :

one of the most ideal systems for studying bandwidth effects. The Sommerfeld-Wilson ratio

(≃ 2),

the Kadowaki-Woods ratio (in the same region as heavy fermion systems), and a large

T^{2}

term in the electric resistivity, even at 300 K, substantiate a large electron correlation in this system, though the effective mass, obtained by thermodynamic and magnetic measurements, shows only a systematic but moderate increase in going from

{SrVO}_{3}

{CaVO}_{3},

in contrast to the critical enhancement expected from the Brinkmann-Rice picture. It is proposed that the metallic properties observed in this system near the Mott transition can be explained by considering the effect of a nonlocal electron correlation.

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