  Two numerical studies, one based on a canonical boundary-value problem and
the other based on a reflection-transmission problem, revealed that the
propagation of high-phase-speed Dyakonov-Tamm (HPSDT) surface waves may be
supported by the planar interface of a chiral sculptured thin film and a
dissipative isotropic dielectric material. Furthermore, many distinct HPSDT
surface waves may propagate in a specific direction, each with a phase speed
exceeding the phase speed of plane waves that can propagate in the isotropic
partnering material. Indeed, for the particular numerical example considered,
the phase speed of an HPSDT surface wave could exceed the phase speed in bulk
isotropic dielectric material by a factor of as much as 10.
