Cluster perturbation study of 1D electron-hole Hubbard model

• Published in: Physica Status Solidi (b) Vol. 245; no. 12; pp. 2729 - 2732
• Main Authors: Asano, Kenichi, Nishida, Takuto, Ogawa, Tetsuo
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.12.2008; WILEY‐VCH Verlag
• Subjects: 71.10.Fd; 71.30.+h; 71.35.−y; 73.21.−b
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200879807

We studied the quarter‐filled electron–hole Hubbard model of one dimension using the cluster perturbation method. We found that the ground states of this system are always insulating as long as the electron–hole attractive interaction has a finite value. The calculated density of states for the electron and hole is significantly renormalized by the interaction, and show energy gaps at the Fermi energy. These gaps are induced by the excitonic mechanism at U > U ′ and by the biexcitonic one at U < U ′, where U (> 0) denotes the electron–electron and hole–hole repulsive interaction, and U ′(< 0) denotes the electron–hole attractive interaction. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)