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A gapless charge mode induced by the boundary states in the half-filled Hubbard open-chain

Tetsuo Deguchi·Ruihong Yue·Koichi Kusakabe
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Abstract

We discuss the ground state and some excited states of the half-filled Hubbard model defined on an open chain with L sites, where only one of the boundary sites has a different value of chemical potential. We consider the case when the boundary site has a negative chemical potential -p and the Hubbard coupling U is positive. By an analytic method we show that when p is larger than the transfer integral some of the ground-state solutions of the Bethe ansatz equations become complex-valued. It follows that there is a ``surface phase transition'' at some critical value p_c; when p p_c.

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Tetsuo Deguchi, Ruihong Yue, Koichi Kusakabe. 1998-07-17. A gapless charge mode induced by the boundary states in the half-filled Hubbard open-chain. https://doi.org/10.1088/0305-4470%2F31%2F36%2F006

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