  Atomic-molecular Bose-Einstein condensates (BECs) offer brand new
opportunities to revolutionize quantum gases and probe the variation of
fundamental constants with unprecedented sensitivity. The recent realization of
spin-orbit coupling (SOC) in BECs provides a new platform for exploring
completely new phenomena unrealizable elsewhere. However, there is no study of
SOC atomic-molecular BECs so far. Here, we find a novel way of creating a
Rashba-Dresselhaus SOC in atomic-molecular BECs by combining the spin dependent
photoassociation and Raman coupling, which can control the formation and
distribution of a new type of topological excitation -- carbon-dioxide-like
Skyrmion. This Skyrmion is formed by two half-Skyrmions of molecular BECs
coupling with one Skyrmion of atomic BECs, where the two half-Skyrmions locates
at both sides of one Skyrmion, which can be detected by measuring the vortices
structures using the time-of-flight absorption imaging technique in real
experiments.
