Dresden 2003 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Tiefe Temperaturen
TT 2: Systeme korrelierter Elektronen I
TT 2.2: Vortrag
Montag, 24. März 2003, 10:15–10:30, HSZ304
Phase Diagram of the Ionic Hubbard Model — •Salvatore Manmana1, Volker Meden2, Reinhard Noack1, and Kurt Schönhammer2 — 1Institut für Theoretische Physik III, Universität Stuttgart, Pfaffenwaldring 57 / V, 70550 Stuttgart — 2Institut für Theoretische Physik, Georg-August-Universität Göttingen, Bunsenstr. 9, 37073 Göttingen
The “Ionic Hubbard Model” consisting of a one-dimensional Hubbard chain with an on-site electron repulsion U and an alternating external potential, was introduced to describe the transition from a neutral to an ionic phase for charge transfer salts and was later also used to describe the transition to a ferroelectric phase e. g. in BaTiO3. The phase diagram of this model has recently been the subject of much discussion in the literature. The controversial issue is the nature of the band-insulator to Mott-insulator transition which occurs with increasing interaction strength. Both a single transition scenario and a scenario with two transition points and an intermediate dimerized phase have been suggested. We present numerical results obtained with the DMRG method (Density Matrix Renormalization Group) which support a two-point scenario with a dimerized intermediate phase.