Strain induced ferroelectricity in GdN: first-principles calculations

Abstract

Using first-principles density functional calculations and the generalized gradientapproximation functional including the on-site Coulomb interaction of 4f orbitals, we showthat ferroelectricity can be induced by appropriate epitaxial tensile strain in GdN with asimple rock-salt structure, and that the polarization is sensitive to the strain. Thecalculated phonon spectra of strained GdN also confirm the existence of ferroelectricpolarization. In addition, the electronic structure and magnetic properties of strainedGdN as a function of strain are investigated. The present work opens up thepossibility of epitaxially tensioned GdN thin films as potential multiferroics.