Impact of geometrical frustration on charge transport near the Mott transition in pyrochlore (Y${}_{1-x}$Cd${}_x$)${}_2$Mo${}_2$O${}_7$

To search for novel spin-charge coupled phenomena in the strongly correlated electron system on a frustration lattice, charge transport and dynamics have been investigated for the hole-doped spin-glass (Mott) insulator (Y${}_{1-x}$Cd${}_x$)${}_2$Mo${}_2$O${}_7$ with pyrochlore structure. Coincident with the disappearance of spin-glass state by hole doping, a diffusive metallic transport with strongly renormalized electron mass shows up with no long range spin order, which is caused by strong antiferromagnetic spin fluctuation due to the geometrical frustration.