2006-2007 Colloquium Series

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NAU Physical Sciences (Bldg 19, Rm 321), Tuesday, 20 February 2007, 4:00 PM
(Refreshments at 3:45pm)

Nanoscale Collective Quantum Effects:
Electric Polarization in Clusters and Thin Films

Kristopher E. Andersen
Naval Research Laboratory

Abstract

Many phenomena in solids, in addition to being of inherent quantum mechanical origin, are collective many-body effects. Examples include superconductivity, ferromagnetism, and ferroelectricity. Whether these phenomena, due to their collective nature, survive in nanoscale systems is an open question of both fundamental and practical interest. One wonders whether there is an abrupt transition governed by an intrinsic length scale or if nascent, yet observable, effects might exist? In this talk, the case of ferroelectricity is considered. First, the modern theory of electric polarization is discussed to give an overview of what is known in bulk (3D) solids. Then first-principles electronic structure calculations are used to gain insight into recent experiments on (0D) niobium clusters and (2D) oxide thin films.

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