Electron EDM searches based on alkali-metal- or alkaline-earth-metal-bearing molecules

We introduce four new molecules - YbRb, YbCs, YbSr$^+$, and YbBa$^+$ - that may prove fruitful in experimental searches for the electric-dipole moment (EDM) of the electron. These molecules can, in principle, be prepared at extremely low temperatures by photoassociating ultracold atoms and therefore may present an advantage over molecular-beam experiments. Here we discuss properties of these molecules and assess the effective electric fields they contribute to an electron EDM measurement.