Browsing by Author "Shih, C. T."
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- Dispersion of a single hole in the t-J modelLee, T. K.; Shih, C. T. (American Physical Society, 1997-03-01)The dispersion of a single hole in the t-J model obtained by the exact result of 32 sites and the results obtained by self-consistent Born approximation and the Green function Monte Carlo method can be simply derived by a mean-field theory with d-wave resonating-valence-bond (d-RVB) and antiferromagnetic order parameters. In addition, it offers a simple explanation for the difference observed between those results. The presence of the extended van Hove region at (pi,0) is a consequence of the (d-RVB pairing instead of the antiferromagnetic order. Results including t' and t '' are also presented and explained consistently in a similar way.
- Systematic scaling in the low-energy excitations of the t-J model in one and two dimensionsEder, R.; Chen, Y. C.; Lin, H. Q.; Ohta, Y.; Shih, C. T.; Lee, T. K. (American Physical Society, 1997-05-01)We present an exact diagonalization study of the low-energy singlet and triplet states for both the one-dimensional (1D) and 2D t-J models. A scan of the parameter ratio J/t shows that for most low-energy states in both 1D and 2D the excitation energy takes the form E(t,J)=a . t+b . J. In 1D this is the natural conse quence of the factorization of the low-energy wave functions, i.e., spin-charge separation. Examination of the low-energy eigenstates in 2D shows that most of these are collective modes, which for larger J correspond to a periodic modulation of the hole density. The modulation is well reproduced by treating holes as hard-core bosons with an attractive interaction.