Low-Energy Polymeric Phases of Alanates

Tran Doan Huan; Maximilian Amsler; Miguel A. L. Marques; Silvana Botti; Alexander Willand; Stefan Goedecker

doi:10.1103/PhysRevLett.110.135502

paper

Low-Energy Polymeric Phases of Alanates

arXiv:1211.0718 · doi:10.1103/PhysRevLett.110.135502

Abstract

Low-energy structures of alanates are currently known to be described by patterns of isolated, nearly ideal tetrahedral [AlH $_{4}$ ] anions and metal cations. We discover that the novel polymeric motif recently proposed for LiAlH $_{4}$ plays a dominant role in a series of alanates, including LiAlH $_{4}$ , NaAlH $_{4}$ , KAlH $_{4}$ , Mg(AlH $_{4}$ ) $_{2}$ , Ca(AlH $_{4}$ ) $_{2}$ and Sr(AlH $_{4}$ ) $_{2}$ . In particular, most of the low-energy structures discovered for the whole series are characterized by networks of corner-sharing [AlH $_{6}$ ] octahedra, forming wires and/or planes throughout the materials. Finally, for Mg(AlH $_{4}$ ) $_{2}$ and Sr(AlH $_{4}$ ) $_{2}$ , we identify two polymeric phases to be lowest in energy at low temperatures.

9 pages, 8 figures, 2 tables, including supplemental material

Low-Energy Polymeric Phases of Alanates

Abstract

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