Breakdown of the Nagaoka phase in the two-dimensional t-J model

Article

关键词: HUBBARD-MODEL;    FERROMAGNETIC STATE;    SQUARE LATTICE;    INSTABILITY;    SEPARATION;    EXCITATIONS;    INSULATORS;   

DOI  :  10.1103/PhysRevB.65.134437

来源: SCIE

【 摘 要 】

In the limit of weak exchange J at low hole concentration delta the ground state of the two-dimensional 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, J(cr)similar totdelta(2), 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 delta and scales as a power of the system size N.

【 授权许可】

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