The propagation of electromagnetic surface waves guided by the planar
interface of two isotropic chiral materials, namely materials \calA and
\calB, was investigated by numerically solving the associated canonical
boundary-value problem. Isotropic chiral material \calB was modeled as a
homogenized composite material, arising from the homogenization of an isotropic
chiral component material and an isotropic achiral, nonmagnetic, component
material characterized by the relative permittivity \eps_a^\calB. Changes in
the nature of the surface waves were explored as the volume fraction
f_a^\calB of the achiral component material varied. Surface waves are
supported only for certain ranges of f_a^\calB; within these ranges only one
surface wave, characterized by its relative wavenumber q, is supported at
each value of f_a^\calB. For \mbox{Re} \lec \eps_a^\calB \ric > 0 , as
\left| \mbox{Im} \lec \eps_a^\calB \ric \right| increases surface waves are
supported for larger ranges of f_a^\calB and \left| \mbox{Im} \lec q \ric
\right| for these surface waves increases. For \mbox{Re} \lec \eps_a^\calB
\ric < 0 , as \mbox{Im} \lec \eps_a^\calB \ric increases the ranges of
f_a^\calB that support surface-wave propagation are almost unchanged but
\mbox{Im} \lec q \ric for these surface waves decreases. The surface waves
supported when \mbox{Re} \lec \eps_a^\calB \ric < 0 may be regarded as akin
to surface-plasmon-polariton waves, but those supported for when \mbox{Re}
\lec \eps_a^\calB \ric > 0 may not