About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
Applied Physics Letters
Paper
Ta2 O5 polymorphs: Structural motifs and dielectric constant from first principles
Abstract
Using large-scale simulations based on density-functional theory we determine the structural properties of several polymorphs of tantalia, their vibrational spectra and dielectric properties. Our calculations indicate that structurally distinct configurations can coexist, having coordination polyhedra that are dissimilar or have different relative arrangements. Interpolyhedra vibrations are discovered to be responsible for sizable changes of the static dielectric constant from one polymorph to the other. Our results for the dielectric constant (both at high and low frequency) are in excellent agreement with experiment and provide an explanation for the different measured values and their claimed dependence on growth conditions. © 2010 American Institute of Physics.