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Large-$U$ limit of a Hubbard model in a magnetic field: chiral spin interactions and paramagnetism

Diptiman Sen·R. Chitra
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Abstract

We consider the large-$U$ limit of the one-band Hubbard model at half-filling on a non-bipartite two-dimensional lattice. An external magnetic field can induce a three-spin chiral interaction at order $1 / U^2 ~$. We discuss situations in which, at low temperatures, the chiral term may have a larger effect than the Pauli coupling of electron spins to a magnetic field. We present a model which explicitly demonstrates this. The ground state is a singlet with a gap; hence the spin susceptibility is zero while the chiral susceptibility is finite and paramagnetic.

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Diptiman Sen, R. Chitra. 1994-12-05. Large-$U$ limit of a Hubbard model in a magnetic field: chiral spin interactions and paramagnetism. https://doi.org/10.1103/physrevb.51.1922

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