  Towards a resolution of the longstanding controversy regarding the existence
of Cu-Li intermetallic compounds, we extensively investigate the phase
stability of Cu-Li intermetallics with various possible stoichiometries at zero
temperature and pressure using a global structure searching method. It is found
that Cu-Li intermetallics can exist stably at atmospheric pressure, and three
stable intermetallics (Fmmm Cu1Li2, Fd m Cu2Li1 and P Cu7Li1,) are identified.
Electronic structure analysis reveals that although the three stable phases are
metallic, covalent Cu-Cu and ionic Cu-Li bonds are found in the three
structures. Moreover, the 3d states of copper atoms are mostly responsible for
bond formations in the Cu-Li intermetallics. For all the predicted Cu-Li
intermetallics, the effect of Cu concentration on structure, mechanical and
thermodynamic properties are calculated systematically.
