  The newly discovered topological Dirac semimetals host the possibilities of
various topological phase transitions through the control of spin-orbit
coupling as well as symmetries and dimensionalities. Here, we report a
magnetotransport study of high-mobility (Cd1-xZnx)3As2 films, where the
topological Dirac semimetal phase can be turned into a trivial insulator via
chemical substitution. By high-field measurements with a Hall-bar geometry,
magnetoresistance components ascribed to the chiral charge pumping have been
distinguished from other extrinsic effects. The negative magnetoresistance
exhibits a clear suppression upon Zn doping, reflecting decreasing Berry
curvature of the band structure as the topological phase transition is induced
by reducing the spin-orbit coupling.
