Departmental Papers (MSE)

Document Type

Journal Article

Date of this Version

3-15-2010

Abstract

Under normal conditions, sodium forms a 1:1 stoichiometric compound with indium, and also with thallium, both in the double-diamond structure. But sodium does not combine with aluminum at all. Could NaAl exist? If so, under what conditions and in which structural types? Instead of beginning with a purely computational and first-principles structure search, we are led to apply the early Brillouin and higher (Jones) zone ideas of the physics determining structural selection. We begin with a brief recapitulation of the higher zone concept as applied to the stability of metals and intermetallic compounds. We then discuss the extension of this concept to problems where density becomes a primary variable, within the second-order band structure approximation. An analysis of the range of applicability of pressure-induced Jones zone activation is presented. The simple NaAl compound serves us as a numerical laboratory for the application of this concept. Higher zone arguments and chemical intuition lead quite naturally to the suggestion that 1:1 compound formation between sodium and aluminum should be favored under pressure and specifically in the double-diamond structure. This is confirmed computationally by density functional theoretic methods within the generalized gradient approximation.

Comments

Suggested Citation:
Feng, J., R. Hoffmann and N.W. Ashcroft. (2010). "Double-diamond NaAl via Pressure: Understanding Structure Through Jones Zone Activation." The Journal of Chemical Physics. 132, 114106.

© 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

The following article appeared in The Journal of Chemical Physics and may be found at http://dx.doi.org/10.1063/1.3328198

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Date Posted: 14 October 2010

This document has been peer reviewed.