  We propose a scheme based on topological insulators to generate Kramers pairs
of Majorana fermions or parafermions in the complete absence of magnetic
fields. Our setup consists of two topological insulators whose edge states are
brought close to an s-wave superconductor. The resulting proximity effect leads
to an interplay between a non-local crossed Andreev pairing, which is dominant
in the strong electron-electron interaction regime, and usual superconducting
pairing, which is dominant at large separation between the two topological
insulator edges. As a result, there are zero-energy bound states localized at
interfaces between spatial regions dominated by the two different types of
pairing. Due to the preserved time-reversal symmetry, the bound states come in
Kramers pairs. If the topological insulators carry fractional edge states, the
zero-energy bound states are parafermions, otherwise, they are Majorana
fermions.
