  Searching for an ideal magnetic Weyl semimetal hosting only a single pair of
Weyl points has been a focal point for systematic clarification of its unique
magnetotransport derived from the interplay between topology and magnetization.
Among the candidates, triangular-lattice antiferromagnet EuCd$_2$As$_2$ has
been attracting special attention due to the prediction of the ideal Weyl
semimetal phase in the ferromagnetic state, however, transport properties of
low-carrier density samples have remained elusive. Here we report molecular
beam epitaxy growth of EuCd$_2$As$_2$ films, achieving low-hole density in the
range of $10^{15}$-$10^{16}$ cm$^{-3}$ at low temperature. Transport
measurements of such low-carrier density films reveal an insulating behavior
with an activation gap of about 200 meV, which persists even in the
field-induced ferromagnetic state. Our work provides an important experimental
clue that EuCd$_2$As$_2$ is intrinsically insulating, contrary to the previous
prediction.
