  The tunable carrier density plays a key role in the investigation of novel
transport properties in three-dimensional topological semimetals. Here we
demonstrate that the carrier density as well as the mobility of Dirac semimetal
Cd3As2 nanoplates can be effectively tuned by the in-situ thermal treatment at
350 K for one hour, both showing a non-monotonic evolution with the thermal
cycling treatments. The upward shift of Fermi level relative to the Dirac nodes
blurs the surface Fermi-arc states, accompanying with an anomalous phase shift
of oscillations of bulk states due to the change of topology of electrons.
Meanwhile, the peaks of oscillations of bulk longitudinal magnetoresistivity
shift at high fields due to their coupling to the oscillations of the surface
Fermi-arc states. Our work provides a thermal control knob for manipulations of
the quantum states through the carrier density in Dirac semimetal Cd3As2 at
high temperature.
