Effect of impurity potentials on antiferromagnetism in two-dimensional Hubbard model

29th International Symposium on Superconductivity

Yokoyama, Hisatoshi^1 ; Sato, Ryo^1 ; Kobayashi, Kenji^2

Department of Physics, Tohoku University, Aoba-ku, Sendai

980-8578, Japan^1

Department of Natural Science, Chiba Institute of Technology, Narashino

275-0023, Japan^2

关键词: Antiferromagnetic state;    Cuprates;    Half-filling;    Hubbard;    Lattice sites;    Randomly distributed;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/871/1/012032/pdf
DOI  :  10.1088/1742-6596/871/1/012032

来源: IOP

【 摘 要 】

Recent numerical studies have shown that antiferromagnetism (AF) prevails widely near half filling in the two-dimensional Hubbard (t-t′-U) model, contrary to the experiments on cuprate superconductors. In cuprates, disorders owing to the dopants, which are usually disregarded in theory, are possibly intrinsic and considerable. Thus, as a first step, we consider the effects of point-type impurity potentials, which are randomly distributed on the lattice sites, on the stability of AF. It is found that a moderate impurity potential does not modify the stability of AF, but a sufficiently strong attractive potential V(V-U) appreciably weakens an antiferromagnetic state owing to an insufficient screening of V.