Hiroyuki Shiba

collaborators

4 papers

cond-mat1996

Ferromagnetism in multi--band Hubbard models: From weak to strong Coulomb repulsion

Karlo Penc, Hiroyuki Shiba, Frédéric Mila +1

We propose a new mechanism which can lead to ferromagnetism in Hubbard models containing triangles with different on-site energies. It is based on an effective Hamiltonian that we…

cond-mat1995

Shadow band in the one-dimensional large $U$ Hubbard model

Karlo Penc, Karen Hallberg, Frederic Mila +1

We show that the factorized wave-function of Ogata and Shiba can be used to calculate the $k$ dependent spectral functions of the one-dimensional, infinite $U$ Hubbard model, and o…

cond-mat1995

Propagating S=1/2 particles in S=1 Haldane gap systems

Karlo Penc, Hiroyuki Shiba

Inspired by the recent experiments on Y $_{2 - x}$ Ca $_{x}$ BaNiO $_{5}$ , (J. F. DiTusa {\it et al.}, Phys. Rev. Lett. 73, 1857 (1994)), we discuss the dispersion relation of the $s$ =1/2 par…

cond-mat1995

Spectral function of the 1D Hubbard model in the $U \to + \infty$ limit

Karlo Penc, Frédéric Mila, Hiroyuki Shiba

We show that the one-particle spectral functions of the one-dimensional Hubbard model diverge at the Fermi energy like $∣ ω - ε_{F} ∣^{- 3/8}$ in the $U \to + \infty$ limit. The…

Ferromagnetism in multi--band Hubbard models: From weak to strong Coulomb repulsion

Shadow band in the one-dimensional large U Hubbard model

Propagating S=1/2 particles in S=1 Haldane gap systems

Spectral function of the 1D Hubbard model in the U→+∞ limit

Shadow band in the one-dimensional large $U$ Hubbard model

Spectral function of the 1D Hubbard model in the $U \to + \infty$ limit