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arXiv · 0803.1855

Dielectric constant boost in amorphous sesquioxides

Pietro Delugas·Vincenzo Fiorentini·Alessio Filippetti
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Abstract

High-kappa dielectrics for insulating layers are a current key ingredient of microelectronics. X2O3 sesquioxide compounds are among the candidates. Here we show for a typical material of this class, ScO3, that the relatively modest dielectric constant of its crystalline phase is enhanced in the amorphous phase by over 40% (from ~15 to ~22). This is due to the disorder-induced activation of low frequency cation-related modes which are inactive or inefficient in the crystal, and by the conservation of effective dynamical charges (a measure of atomic polarizability). The analysis employs density-functional energy-force and perturbation-theory calculations of the dielectric response of amorphous samples generated by pair-potential molecular dynamics.

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Pietro Delugas, Vincenzo Fiorentini, Alessio Filippetti. 2008-03-12. Dielectric constant boost in amorphous sesquioxides. https://doi.org/10.1063/1.2917797

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