Pressure-induced structural phase transition in NaBH4
2005 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, Vol. 72, no 5, 054125- p.Article in journal (Refereed) Published
We present a combined experimental and theoretical study of the technologically important NaBH4 compound under high pressure. Using Raman spectroscopy at room temperature, we have found that NaBH4 undergoes a structural phase transformation starting at 10.0 GPa with the pure high-pressure phase being established above 15.0 GPa. In order to compare the Raman data recorded under high pressure with the low-temperature tetragonal phase of NaBH4, we have also performed a cooling experiment. The known order-disorder transition from the fcc to the tetragonal structure was then observed. However, the new high pressure phase does not correspond to this low-temperature structure. Using first-principle calculations based on the density functional theory, we show that the high-pressure phase corresponds to the alpha-LiAlH4–type structure. We have found a good agreement between the measured and calculated transition pressures. Additionally, we present the electronic structure of both the fcc and the high-pressure phases.
Place, publisher, year, edition, pages
2005. Vol. 72, no 5, 054125- p.
Hydride, hydrogen storage, NaBH4, high pressure, phase diagram, phase transition, orientational ordering transition, Raman spectroscopy, tetragonal, cubic, order-disorder, density functional theory, DFT, first principles calculations
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:umu:diva-8528DOI: doi:10.1103/PhysRevB.72.054125OAI: oai:DiVA.org:umu-8528DiVA: diva2:148199