Crystal-lattice modulation of the metal-insulator transition system PrRu4P12 studied by X-ray diffraction

PrRu4P12 exhibits a metal-insulator phase transition at T-MI = 60 K: In the insulating phase below T-MI, X-ray superlattice reflections characterized by the wave vector q(0) = [1, 0, 0] were observed. The intensities at various reciprocal-lattice positions are reproduced by a model of modulated structure with the space group Pm(3) over bar in which Ru and P displacements are about 0.074% and 0.06%, respectively of the lattice constant. Thus, the transition can be interpreted as the gap formation due to the nesting of Fermi surface with 2k(F) = [1, 0; 0]. (C) 2004 Elsevier B.V. All rights reserved.