Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.32: Poster

Mittwoch, 29. März 2006, 14:30–18:30, P1

Competing phases of the t−J model on the triangular lattice. — •Irakli Titvinidze¹ and Matthias Vojta² — ¹Institut fuer Theoretische Physik A, RWTH Aachen, Templergraben 55, 52056 Aachen, Germany — ²Institut fuer Theorie der Kondensierten Materie,Universitaet Karlsruhe, Postfach 6980, 76128 Karlsruhe, Germany

Our aim is to study the t−J model on a triangular lattice, employing the Sp(2N) large-N mean-field theory used previously [1,2] for the square-lattice geometry.

Our calculations show that for low doping a spin-Peierls state is realized in the system, while for high doping s-wave superconductivity occurs. For intermediate doping two different phases with a single-site unit cell appear: For small t/J we find a symmetry-broken phase with links fields |Q₁|=|Q₂|>|Q₃|, whereas for large t/J a “120^o phase” is realized, with Q₁=Q₂ e^{2π i/3} = Q₃ e^{4π i/3}. This is in qualitative agreement with published results of Kumar and Shastry [3] and Ogata [4].

[1] S. Sachdev and N. Read, Int. J. Mod. Phys. B 5, 219 (2000)

[2] M. Vojta, Y. Zhang, and S. Sachdev, Phys. Rev. B 62, 6721 (2000)

[3] B. Kumar and B. S. Shastry, cond-mat/0304210

[4] M. Ogata, cond-mat/0304405