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The breakdown of the Nagaoka phase in the 2D t-J model

E. Eisenberg·R. Berkovits·D. A. Huse·B. L. Altshuler
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Abstract

In the limit of weak exchange, J, at low hole concentration, the ground state of the 2D t-J model is believed to be ferromagnetic. We study the leading instability of this Nagaoka state, which emerges with increasing J. Both exact diagonalization of small clusters, and a semiclassical analytical calculation of larger systems show that above a certain critical value of the exchange, Nagaoka's state is unstable to phase separation. In a finite-size system a bubble of antiferromagnetic Mott insulator appears in the ground state above this threshold. The size of this bubble depends on the hole concentration and scales as a power of the system size, N.

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E. Eisenberg, R. Berkovits, D. A. Huse, B. L. Altshuler. 2002-01-17. The breakdown of the Nagaoka phase in the 2D t-J model. https://doi.org/10.1103/physrevb.65.134437

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