Valence change and physical properties in semiconducting mixed-valent rare-earth compounds

摘要: Abstract Ce 3 Pt Sb 4 is a mixed-valent rare-earth semiconductor, the ground state properties of which can be explained by band theory based on an itineract electron model for 4f electrons. On other hand, isostructural compound Au also semiconductor with resistivity 22ω cm at 0.13 K, but magnetic susceptibility and inelastic neutron scattering show that electrons are well defined to localized 1 state. In latter, no clear anomaly in thermomagnetic curve down 0.5 K has been observed. However, there existsa broad peak 1.5 specific heat ( C / T 2500 mJ/mole 2 ) peak, symmetrical against log , shifts towards higher temperature side under influence field. this sense, good candidate study Kondo effect insulator.