Existence of the Spin-Wave Gap in a Deformed Flat-Band Hubbard Model

2004/11/13 by Makoto Homma, Homma, Makoto
Mathematics · Physics and Astronomy · #FOS: Physical sciences #Mathematical Physics (math-ph) #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.str-el #math-ph #math.MP

paper · pdf · doi:10.48550/arxiv.cond-mat/0411362

30 pages, 1 figure

arxiv created 2004/11/13 · arxiv updated 2009/12/01

Abstract

We consider a deformed flat-band Hubbard model under a periodic boundary condition in arbitrary dimensions. We show that the ground state is only all-spin-up or -down state. We obtain upper and lower bounds of the one-magnon spin-wave energy with an arbitrary momentum. This dispersion relation is the same as that in the XXZ model in the certain parameter region. Therefore the spin wave has a finite energy gap. These results suggests the our model and the XXZ model.

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