@article{oai:niigata-u.repo.nii.ac.jp:00002253,
 author = {Ono, Y. and Mitsumoto, K.},
 journal = {Physica. B, Condensed matter, Physica. B, Condensed matter},
 month = {May},
 note = {We investigate the two-orbital periodic Anderson model with f2-configuration by using the dynamical mean-field theory in which the effective impurity Anderson model is solved using the exact diagonalization method. The renormalization factor Z and the local moment 〈S2〉 are obtained as functions of the Coulomb interaction U, the exchange (Hund's rule) coupling J and the crystal-field splitting Δ. When the ionic ground state is triplet for Δ<Δc=3J, the heavy fermion state with the mass enhancement m*/m=Z-1≳100 together with 〈S2〉～2 is realized in the strong correlation regime for U≳W, where W is the conduction bandwidth. When the ionic ground state is singlet for Δ>Δc, m*/m～1 and 〈S2〉～0 for any value of U. When the singlet ground state and the triplet excited state form a quasi-quartet for Δ≳Δc, the system shows a moderate mass enhancement m*/m～10–100.},
 pages = {694--695},
 title = {Heavy Fermions in the Periodic Anderson Model with Singlet-Triplet Crystal-Field Levels},
 volume = {378-380},
 year = {2006}
}