Nanoscale smoothing and the analysis of interfacial charge and dipolar densities

Javier Junquera, Morrel H. Cohen, Karin M. Rabe

Research output: Contribution to journalArticlepeer-review

88 Scopus citations


The interface properties of interest in multilayers include interfacial charge densities, dipole densities, band offsets, and screening lengths, among others. Most such properties are inaccessible to direct measurements, but are key to understanding the physics of the multilayers. They are contained within first-principles electronic structure computations but are buried within the vast amount of quantitative information those computations generate. Thus far, they have been extracted from the numerical data by heuristic nanosmoothing procedures which do not necessarily provide results independent of the smoothing process. In the present paper we develop the theory of nanosmoothing, establishing procedures for both unpolarized and polarized systems which yield interfacial charge and dipole densities and band offsets invariant to the details of the smoothing procedures when the criteria we have established are met. We show also that dipolar charge densities, i.e.the densities of charge transferred across the interface, and screening lengths are not invariant. We illustrate our procedure with a toy model in which real, transversely averaged charge densities are replaced by sums of Gaussians.

Original languageEnglish (US)
Article number213203
JournalJournal of Physics Condensed Matter
Issue number21
StatePublished - May 30 2007

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics


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