Influence of electric polarization on Coulomb blockade in a super-paraelectric clusters assembly

We study electron transport in an assembly of epitaxial Cr2O3 nanoparticles embedded in a MgO tunnel barrier: an unusual variation in the Coulomb blockade charging energy is observed as a function of the size of the clusters. In striking contrast to the expected increase in charging energy when decreasing the cluster size, an almost constant behavior is observed. We argue here that the spontaneous superparaelectric moment carried by the cluster core is the origin of this unusual behavior since it drives the dielectric constant in this cluster assembly. This phenomenon could be exploited to fabricate devices with single valued Coulomb blockade energy despite a statistical dispersion in the cluster size.We study electron transport in an assembly of epitaxial Cr2O3 nanoparticles embedded in a MgO tunnel barrier: an unusual variation in the Coulomb blockade charging energy is observed as a function of the size of the clusters. In striking contrast to the expected increase in charging energy when decreasing the cluster size, an almost constant behavior is observed. We argue here that the spontaneous superparaelectric moment carried by the cluster core is the origin of this unusual behavior since it drives the dielectric constant in this cluster assembly. This phenomenon could be exploited to fabricate devices with single valued Coulomb blockade energy despite a statistical dispersion in the cluster size.