Electronic dynamics and plasmons of sodium under compression
2011 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 108, no 51, 20434-20437 p.Article in journal (Refereed) Published
Sodium, which has long been regarded as one of the simplest metals, displays a great deal of structural, optical, and electronic complexities under compression. We compressed pure Na in the body-centered cubic structure to 52 GPa and in the face-centered cubic structure from 64 to 97 GPa, and studied the plasmon excitations of both structures using the momentum-dependent inelastic X-ray scattering technique. The plasmon dispersion curves as a function of pressure were extrapolated to zero momentum with a quadratic approximation. As predicted by the simple free-electron model, the square of the zero-momentum plasmon energy increases linearly with densification of the body-centered cubic Na up to 1.5-fold. At further compressions and in face-centered cubic Na above 64 GPa, the linear relation curves progressively toward the density axis up to 3.7-fold densification at 97 GPa. Ab initio calculations indicate that the deviation is an expected behavior of Na remaining a simple metal.
Place, publisher, year, edition, pages
2011. Vol. 108, no 51, 20434-20437 p.
high pressure, free-electron gas, generalized gradient approximation, alkali metal
IdentifiersURN: urn:nbn:se:uu:diva-166723DOI: 10.1073/pnas.1116930108ISI: 000298289400041OAI: oai:DiVA.org:uu-166723DiVA: diva2:477650