  Layered non-centrosymmetric bismuth tellurohalides are being examined as
candidates for topological insulators. Pressure is believed to be essential for
inducing and tuning topological order in these systems. Through electrical
transport and Raman scattering measurements, we find superconductivity in two
high-pressure phases of BiTeCl with the different normal state features,
carrier characteristics, and upper critical field behaviors. Superconductivity
emerges when the resistivity maximum or charge density wave is suppressed by
the applied pressure and then persists till the highest pressure of 51 GPa
measured. The huge enhancement of the resistivity with three magnitude of
orders indicates the possible achievement of the topological order in the dense
insulating phase. These findings not only enrich the superconducting family
from topological insulators but also pave the road on the search of topological
superconductivity in bismuth tellurohalides.
