2004/05/06 by S. H. Curnoe, H. Harima, Hisatomo Harima +4 · 1 citation
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Magnetic Properties of Alloys #Rare-earth and actinide compounds #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.70.245112
published as Phys. Rev. B 70, 245112 (2004) · 6 pages
arxiv created 2004/05/06 · openalex publication_date 2004/12/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
All symmetry-allowed couplings between the 4f2-electron ground state doublet of trivalent praseodymium in PrRu4P12 and PrFe4P12 and displacements of the phosphorus, iron, or ruthenium ions are considered. Two types of displacements can change the crystal lattice from body-centred cubic to simple orthorhombic or to simple cubic. The first type lowers the point group symmetry from tetrahedral to orthorhombic, while the second type leaves it unchanged, with corresponding space group reductions Im3\ensuremath→Pmmm and Im3\ensuremath→Pm3, respectively. In former case, the lower point group symmetry splits the degeneracy of the 4f2 doublet into states with opposite quadrupole moment, which then leads to antiquadrupolar ordering, as in PrFe4P12. Either kind of displacement may conspire with nesting of the Fermi surface to cause the metal-insulator or partial metal-insulator transition observed in PrFe4P12 and PrRu4P12. We investigate this scenario using band-structure calculations, and it is found that displacements of the phosphorus ions in PrRu4P12 (with space-group reduction Im3\ensuremath→Pm3) open a gap everywhere on the Fermi surface.