  We present anisotropic transport and optical spectroscopy studies on
EuCd_2As_2. The measurements reveal that EuCd_2As_2 is a low carrier density
semimetal with moderate anisotropic resistivity ratio. The charge carriers
experience very strong scattering from Eu magnetic moments, resulting in a
Kondo-like increase of resistivity at low temperature. Below the
antiferromagnetic transition temperature at $T_N$= 9.5 K, the resistivity drops
sharply due to the reduced scattering from the ordered Eu moments.
Nevertheless, the anisotropic ratio of $\rho_c/\rho_{ab}$ keeps increasing,
suggesting that the antiferromagnetic coupling is along the c-axis. The optical
spectroscopy measurement further reveals, besides an overdamped reflectance
plasma edge at low energy, a strong coupling between phonon and electronic
continuum. Our study suggests that EuCd_2As_2 is a promising candidate
displaying intriguing interplay among charge, magnetism and the underlying
crystal lattice.
