Interplay between Coulomb interaction and hybridization in Ca and anomalous pressure dependence of resistivity
D. Y. Novoselov+*, D. M. Korotin+, A. O. Shorikov+*, A. R. Oganov×°, V. I. Anisimov+*
+M. N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Yekaterinburg, Russia
*Department of theoretical physics and applied mathematics, Ural Federal University, 620002 Yekaterinburg, Russia
×Skolkovo Institute of Science and Technology, 143026 Moscow, Russia
°Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
Abstract
Increasing external pressure gives rise to
s-d electron transfer in calcium that results in the localization of the
charge density in the interstices of the crystal structure, i.e., the formation of an electride.
The corresponding electronic states are partially
filled and localized and, hence, electronic correlations could arise.
We have carried out theoretical calculations for the high-pressure phases
of Ca taking into account the Coulomb interactions between the
electronic states centered on the interstitial site.
The results of our calculations and proposed microscopic model showed
that the structural phase transition under high pressure is due to an
interplay of hybridization and correlation effects.
Furthermore, it was found that the Coulomb repulsion can explain the
experimentally observed anomalous
increase of resistivity of the simple cubic phase of calcium under pressure.