  HoSbTe was predicted to be a weak topological insulator, whose spin-orbit
coupling (SOC) gaps are reported to be as large as hundreds of meV. Utilizing
infrared spectroscopy, we find that the compound is of metallic nature from 350
K down to 10 K. Particularly, both of its itinerant carrier density and
scattering rate are demonstrated to decrease with temperature cooling, which is
responsible for the appearance of a broad hump feature in the temperature
dependent resistivity around 200 K. More importantly, we reveal the appearance
of a charge density wave (CDW) gap in addition to the SOC related gap. The
energy scale of the CDW gap is identified to be 364 meV at 10 K, which shift to
252 meV at 350 K. The coexistence of CDW and SOC gaps in the same compound
paves a new avenue to explore more intriguing physics.
