Effects of Higher Hopping Terms on the Stripe States in the Two-Dimensional Hubbard Model
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Using the variational Monte Carlo method for the two-dimensional t-t′-t″-U Hubbard model, we discuss the ground state of the underdoped region on the high-T c cuprates. We found that, while stripe states with the periodicity consistent with experiments for La2− x Sr x CuO4 are stabilized in the case of t′/t < 0, the positive t′/t makes the stripe state unstable with the lowest energy state being the commensurate AF state, which is consistent with experiments on the electron doping system such as Nd2− x Ce x CuO4. We also show that the stripe state is sensitive to the value of t″/t > 0. These results indicate that the nesting condition is a critical factor to the stripe instability.
KEY WORDS:two-dimensional Hubbard model cuprates hopping terms
One of the authors (M. M.) was supported by a Grant-in-Aid for 21st COE Program from the MEXT of the Japanese Government. VMC calculations were performed on Aoyama Plus Systems as well as on the group's facility of AIST.
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