Sodium: A Charge-Transfer Insulator at High Pressures

TitleSodium: A Charge-Transfer Insulator at High Pressures
Publication TypeJournal Article
Year of Publication2010
Gatti, M, Tokatly, IV, Rubio, A
JournalPhysical Review Letters
Volume104
Pagination216404
Date Published2010/May//
Keywordspaper
Abstract

By first-principles methods we analyze the optical response of transparent dense sodium as a function of applied pressure. We discover an unusual kind of charge-transfer exciton that proceeds from the interstitial distribution of valence electrons. The absorption spectrum is strongly anisotropic, which, just at pressures above the metal-insulator transition, manifests as sodium being optically transparent in one direction but reflective in the other. This result provides key information about the crystal structure of transparent sodium, a new unconventional inorganic electride.

URLhttp://dx.doi.org/10.1103/PhysRevLett.104.216404
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