Interatomic potential that describes martensitic phase transformations in pure lithium

An interatomic potential for the pure lithium system is developed on the basis of the second nearest-neighbor modified embedded-atom method formalism, utilizing the force-matching method with a DFT database of various atomic configurations. The developed potential accurately reproduces fundamental physical properties including an unusual order of surface energies of the bcc lithium, (1 0 0) < (1 1 0) < (1 1 1). Subsequent molecular dynamics simulations verify that the present potential can be successfully applied to study martensitic phase transformations of pure lithium at low temperatures. The present results provide detailed insights into the formation of a disordered polytype structure consisting of short-ranged fcc- and hcp-type stacking sequences supporting the experimental observation of this structure in high-purity lithium.