Exact ferromagnetic ground state of pentagon chains

Miklós Gulácsi, György Kovács, Zsolt Gulácsi

Research output: Contribution to journalArticle

8 Citations (Scopus)


We model conducting pentagon chains with a multi-orbital Hubbard model and prove that well below half filling, exact ferromagnetic ground states appear. The rigorous method we use is based on the transformation of original hamiltonian into positive semidefinite form. This technique is independent of the spatial dimension and does not require integrability of the model. The obtained ferromagnetism is connected to dispersionless bands but in a much broader sense than flat-band ferromagnetism requires, where on every site a Hubbard term is present. In our case, only a small percentage of, even randomly distributed, sites are only interacting.

Original languageEnglish
Pages (from-to)269-277
Number of pages9
JournalPhilosophical Magazine Letters
Issue number5
Publication statusPublished - May 4 2014


  • conducting polymers
  • exact ground states
  • ferromagnetism
  • strongly correlated electron systems

ASJC Scopus subject areas

  • Condensed Matter Physics

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