Results of computational investigations of the structural and electronic properties of the ground states of binary compounds LiB x with 0.67 ≤x≤1.00 under pressure are reported. Structure predictions based on evolutionary algorithms and particle swarm optimization reveal that with increasing pressure, stoichiometric 1:1-LiB undergoes a variety of phase transitions, is significantly stabilized with respect to the elements and takes up a diamondoid boron network at high pressures. The Zintl picture is very useful in understanding the evolution of structures with pressure. The experimentally seen finite range of stability for LiB x phases with 0.8≤x≤1.00 is modeled both by boron-deficient variants of the 1:1-LiB structure and lithium-enriched intercalation structures. We find that the finite stability range vanishes at pressures P≥40GPa, where stoichiometric compounds then become more stable. A metal-to-insulator transition for LiB is predicted at P = 70 GPa. © 2012 American Physical Society.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): k128
Acknowledgements: A. Hermann, N. W. Ashcroft, and R. Hoffmann are grateful for support from EFree, an Energy Frontier Research Center funded by the U.S. Department of Energy (Grant No. DESC0001057 at Cornell), and from the National Science Foundation (Grant No. CHE-0910623 and No. DMR-0907425). Computational resources provided by the Cornell NanoScale Facility (supported by the National Science Foundation through Grant No. ECS-0335765), the XSEDE network (provided by the National Center for Supercomputer Applications through Grant No. TG-DMR060055N), and the KAUST Supercomputing Laboratory (Project ID k128) are gratefully acknowledged. A. Bergara, I. G. Gurtubay, and A. Suarez-Alcubilla are grateful to the Department of Education, Universities and Research of the Basque Government, UPV/EHU (Grant No. IT-366-07) and the Spanish Ministry of Science and Innovation (Grants No. FIS2010-19609-C02-00 and No. FIS2009-09631) for Financial support.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.