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】
Free