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arXiv · 2604.22017

How Electrons Become Mobile in a Colossal Dielectric -- Fe$_2$TiO$_5$

M. L. McLanahan·A. P. Ramirez
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Abstract

We measure the colossal permittivity in single crystal Fe$_2$TiO$_5$ using broadband spectroscopy in the frequency range 20 Hz - 1 MHz. The relaxation response is analyzed using a Debye-like model with Arrhenius activation in two different ways and yields an energy barrier of 286.1 $\pm$ 2.8 meV. DC transport yields an activation energy of 288.8 $\pm$ 2.8 meV. These results strongly imply that the energy barrier for localized dipole motion and itinerant charge transport originate from the same atom-level forces. A further implication is that colossal dielectric behavior is a microscopic bulk phenomenon arising from a system on brink of metallicity.

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M. L. McLanahan, A. P. Ramirez. 2026-04-23. How Electrons Become Mobile in a Colossal Dielectric -- Fe$_2$TiO$_5$. https://arxiv.org/abs/2604.22017

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