title: Computational Approach for Epitaxial Polymorph Stabilization through Substrate Selection.
abstract: With the ultimate goal of finding new polymorphs through targeted synthesis conditions and techniques, we outline a computational framework to select optimal substrates for epitaxial growth using first principle calculations of formation energies, elastic strain energy, and topological information. To demonstrate the approach, we study the stabilization of metastable VO2 compounds which provides a rich chemical and structural polymorph space. We find that common polymorph statistics, lattice matching, and energy above hull considerations recommends homostructural growth on TiO2 substrates, where the VO2 brookite phase would be preferentially grown on the a-c TiO2 brookite plane while the columbite and anatase structures favor the a-b plane on the respective TiO2 phases. Overall, we find that a model which incorporates a geometric unit cell area matching between the substrate and the target film as well as the resulting strain energy density of the film provide qualitative agreement with experimental observations for the heterostructural growth of known VO2 polymorphs: rutile, A and B phases. The minimal interfacial geometry matching and estimated strain energy criteria provide several suggestions for substrates and substrate-film orientations for the heterostructural growth of the hitherto hypothetical anatase, brookite, and columbite polymorphs. These criteria serve as a preliminary guidance for the experimental efforts stabilizing new materials and/or polymorphs through epitaxy. The current screening algorithm is being integrated within the Materials Project online framework and data and hence publicly available.
authors.affiliation: Energy Technologies, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Hong
authors.initials: H
authors.lastname: Ding
authors.affiliation: Energy Technologies, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Shyam S
authors.initials: SS
authors.lastname: Dwaraknath
authors.affiliation: Materials Chemistry Science and Technology, National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
authors.forename: Lauren
authors.initials: L
authors.lastname: Garten
authors.affiliation: Materials Chemistry Science and Technology, National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
authors.forename: Paul
authors.initials: P
authors.lastname: Ndione
authors.affiliation: Materials Chemistry Science and Technology, National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
authors.forename: David
authors.initials: D
authors.lastname: Ginley
authors.affiliation: Energy Technologies, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.|Department of Materials Science and Engineering, University of California Berkeley , Berkeley, California 94704, United States.
authors.forename: Kristin A
authors.initials: KA
authors.lastname: Persson
keywords: elastic energy; epitaxy; heteroepitaxy; homoepitaxy; substrate selection; topology