Heavy fermions in the periodic Anderson model with singlet–triplet crystal-field levels

✍ Scribed by Y. Ōno; K. Mitsumoto

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 110 KB
• Volume: 378-380
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2006.01.224

✦ Synopsis

We investigate the two-orbital periodic Anderson model with f 2 -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 hS 2 i are obtained as functions of the Coulomb interaction U, the exchange (Hund's rule) coupling J and the crystal-field splitting D. When the ionic ground state is triplet for DoD c ¼ 3J, the heavy fermion state with the mass enhancement m à =m ¼ Z À1 \100 together with hS 2 i$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 DbD c , m à =m$1 and hS 2 i$0 for any value of U. When the singlet ground state and the triplet excited state form a quasiquartet for D\D c , the system shows a moderate mass enhancement m à =m$102100.