  A microscopic model is proposed for the scalar order in PrFe4P12 where f2
crystalline electric field (CEF) singlet and triplet states interact with two
conduction bands. By combining the dynamical mean-field theory and the
continuous-time quantum Monte Carlo, we obtain an electronic order with
staggered Kondo and CEF singlets with the total conduction number being unity
per site. The ground state becomes semimetallic provided that the two
conduction bands have different occupation numbers. This model naturally
explains experimentally observed properties in the ordered phase of PrFe4P12
such as the scalar order parameter, temperature dependence of the resistivity,
field-induced staggered moment, and inelastic features in neutron scattering.
The Kondo effect plays an essential role for ordering, in strong contrast with
ordinary magnetic orders by the RKKY interaction.
