DPG Phi
Verhandlungen
Verhandlungen
DPG

Regensburg 2010 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 27: CE: Poster Session

TT 27.44: Poster

Mittwoch, 24. März 2010, 14:00–18:00, Poster D1

On the existence of the excitonic insulator phase in the extended Falicov-Kimball model: a vectorial slave-boson approach — •Bernd Zenker1, Dieter Ihle2, Franz Xaver Bronold1, and Holger Fehske11Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald, Germany — 2Institut für Theoretische Physik, Universität Leipzig, 04109 Leipzig, Germany

Motivated by the possibility of pressure-induced exciton condensation in intermediate-valence Tm[Se,Te] compounds we study the Falicov-Kimball model extended by a finite f-hole valence bandwidth. Within slave-boson mean-field theory we show that coherence between c- and f-states may be established at low temperatures, leading to an excitonic insulator (EI) phase. Thereby our vectorial slave-boson approach overcomes (i) the difficulties of the scalar slave-boson scheme by describing the EI state, and yields (ii) a substantial reduction of the critical temperatures in comparison to those of the standard Hartree-Fock approach. Analyzing the partial densities of states we find strong evidence that the EI typifies either a BCS condensate of electron-hole pairs (weak-coupling regime) or a Bose-Einstein condensate (BEC) of preformed excitons (strong-coupling regime), which points towards a BCS-BEC transition scenario as Coulomb correlations increase.

100% | Mobil-Ansicht | English Version | Kontakt/Impressum/Datenschutz
DPG-Physik > DPG-Verhandlungen > 2010 > Regensburg