Electronic Structure of Plutonium Monochalcogenides
The anomalous properties of the Plutonium (Pu) monochalcogenides are investigated on the basis of electronic structure calculations. The Pu monochalcogenides are calculated to be semi-metallic because, first the large spin-orbit interaction of the Pu 5f states splits the 5f(5/2) and 5f(7/2) sub-bands away from the Fermi energy, and second the hybridisation between Pu 6d and chalcogenide p and 5f bands leads to a hybridisation gap. The anomalous lattice constants, which corresponds neither to Pu(2+) nor Pu(3+) are consisted with the energy band approach, as it is the lattice constant where the transition to Pu(2+) is expected. Our calculations suggest that the Pu has a 5f(6-x)6d(x) configuration, where x depends on the lattice parameter, but the sum of 5f and 6d occupancy is constant. Calculations of the optical conductivity spectra show that there are two optical pseudo-gaps, one of about 20 meV and one of 0.2 eV. A magnetic phase transition is predicted to occur in the NaCl structure under pressure. When this phase transition is enforced in a magnetic field and takes place before the martenitic transition to the CsCl structure occurs, it is predicted to lead to a giant magnetic resistance of about -85%.
Bibliographic Reference: Article: Physical Review B Condensed Matter, Vol.61 No.19 (2000) pp12 825-12 834.
Record Number: 200012809 / Last updated on: 2000-11-03
Original language: en
Available languages: en