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Helicity Modulus and Effective Hopping in the Two-Dimensional Hubbard Model Using Slave-Boson Methods

P. J. H. Denteneer·M. Blaauboer
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Abstract

The slave-boson mean-field method is used to study the two-dimensional Hubbard model. A magnetic phase diagram allowing for paramagnetism, weak- and strong ferromagnetism and antiferromagnetism, including all continuous and first-order transitions, is constructed and compared to the corresponding phase diagram using the Hartree-Fock approximation (HFA). Magnetically ordered regions are reduced by a factor of about 3 along both the $t/U$ and density axes compared to the HFA. Using the spin-rotation invariant formulation of the slave-boson method the helicity modulus is computed and for half-filling is found to practically coincide with that found using variational Monte Carlo calculations using the Gutzwiller wave function. Off half-filling the results can be used to compare with Quantum Monte Carlo calculations of the effective hopping parameter. Contrary to the case of half-filling, the slave-boson approach is seen to greatly improve the results of the HFA when off half-filling. (Submitted to: Journal of Physics: Condensed Matter)

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P. J. H. Denteneer, M. Blaauboer. 1994-06-23. Helicity Modulus and Effective Hopping in the Two-Dimensional Hubbard Model Using Slave-Boson Methods. https://doi.org/10.1088/0953-8984%2F7%2F1%2F014

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