Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 30: CE: Low-dimensional Systems - Models 1
TT 30.5: Vortrag
Donnerstag, 25. März 2010, 10:30–10:45, H20
Zero Temperature Phase Diagram of the 1D t-J Model with Density Matrix Renormalization Group — •Alexander Moreno1, Alejandro Muramatsu1, and Salvatore Manmana2 — 1Institut für Theoretische Physik III, Universität Stuttgart, Germany — 2Institute of Theoretical Physics, Condensed Matter Theory, Lausanne, Switzerland
We study the ground state properties of the one-dimensional t-J model using the Density Matrix Renormalization Group (DMRG), obtaining its phase diagram. We found at low densities that the phase separation region is shifted to higher values of J/t in comparison to previous results [1,2,3]. We confirmed also the results of M. Nakamura et al. [4] who claim, in contrast to other studies [2,3], that a spin gap region is present at densities higher than 0.25. We show that on going from the LL to the spin-gap phase, electrons form pairs visible in real space. The density in real shows also an evidence of the existence of a very small region of the phase diagram where a four electron bound state can be found, as was first suggested by M. Ogata et al. [1]
[1] M. Ogata, M. U. Luchini, S. Sorella, and F. Assaad, Phys. Rev. Lett. 66, 2388 (1991).
[2] C. Y. Chen and T. K. Lee, Phys. Rev. B. 47, 17 (1993).
[3] C. S. Hellberg and E. J. Mele, Phys. Rev. B. 48, 1 (1993).
[4] M. Nakamura, K. Nomura, and Kitazawa, Phys. Rev. Lett. 79, 3214 (1997).