Interplay between the Coulomb Interaction and Hybridization in Ca and Anomalous Pressure Dependence of the Resistivity

• Published in: JETP letters 2019-03, Vol.109 (6), p.387-391
• Main Authors: Novoselov, D. Y., Korotin, D. M., Shorikov, A. O., Oganov, A. R., Anisimov, V. I.
• Format: Article
• Language: English
• Subjects: Atomic; Biological and Medical Physics; Biophysics; Calcium; Charge density; Condensed Matter; Crystal structure; Electrical resistivity; Electron states; Electron transfer; External pressure; Interstices; Molecular; Optical and Plasma Physics; Particle and Nuclear Physics; Phase transitions; Physics; Physics and Astronomy; Pressure dependence; Quantum Information Technology; Solid State Physics; Spintronics
• ISSN: 0021-3640; 1090-6487
• DOI: 10.1134/S0021364019060043

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 in resistivity of the simple cubic phase of calcium under pressure.