Egxact ground states for the periodic Anderson model at half filling in two dimensions

Keiko Kimura, Yasuhiro Hatsugai, Mahito Komoto +2 more

Yasuo Imai, N. Kawakami

Tetsuro Saso

Kazuo Ueda, Hirokazu Tsunetsugu, Manfred Sigrist

It is proved that the ground state of the symmetric periodic Anderson model forms a total spin singlet at half filling. This result can also be applied to the Kondo lattice model, at least for the weak and the very strong antiferromagnetic-coupling limit. For the strong coupling limit of the Kondo lattice it is additionally proved that the singlet ground state exists even when two holes are doped to the half-filled band.

Zsolt Gulácsi

Kensuke Kimura, Yasuhiro Hatsugai, Mahito Kohmoto

A one-parameter family of models interpolates between the periodic Anderson model with infinite repulsion at half-filling and a model whose ground state is exactly the resonating-valence-bond state. It is shown numerically that the excitation gap does not collapse. Therefore the ground states of the two models are adiabatically connected.