Robustness of the ferromagnetism in flat bands

✍ Scribed by Koichi Kusakabe; Hideo Aoki

• Book ID: 103940326
• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 167 KB
• Volume: 194-196
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(94)90437-5

✦ Synopsis

Ferromagnetism in the Hubbard models having flat bands proposed by Mielke and by Tasaki is shown to survive even when the bands become dispersive in a finite region in the phase diagram against Hubbard U and the band parameter. The charge gap in the excitation spectrum and a finite spin stiffness in the strong-coupling limit also indicate that the ferromagnetism is stable against perturbations in the thermodynamic limit.