  Heavy polar diatomic molecules are the leading candidates in searches for the
permanent electric dipole moment of the electron (eEDM). Next-generation eEDM
search experiments ideally require extremely large coherence times, in large
ensembles of trapped molecules that have a high sensitivity to the eEDM. We
consider a family of molecules, mercury-alkali diatomics, that can be feasibly
produced from ultracold atoms. We present calculations of the effective
electric fields experienced by the electron in these molecules. The combination
of reasonably large effective electric fields, and a straightforward path to
obtaining trapped ultracold samples, lead us to identify these molecules as
favorable candidates for eEDM search experiments.
