RKKY interaction in bilayer graphene

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:396

Article

Mohammadi, Yawar¹  Moradian, Rostam^2,3 

[1] Islamic Azad Univ, Kermanshah Branch, Young Researchers & Elite Club, Kermanshah, Iran

[2] Razi Univ, Dept Phys, Kermanshah, Iran

[3] Razi Univ, Nano Sci & Nano Technol Res Ctr, Kermanshah, Iran

关键词: Bilayer graphene;    RKKY interaction;    Tight-binding model;    Green's function;   

DOI  :  10.1016/j.jmmm.2015.07.094

来源: Elsevier

【 摘 要 】

We study the RKKY interaction between two magnetic impurities located on the same layer (intralayer case) or on different layers (interlayer case) in undoped bilayer graphene (BEG) in the four-bands model, by directly calculating the Green functions in the eigenvalues and eigenvectors representation. Our results show that both intra- and interlayer RKKY interactions between two magnetic impurities located on the same (opposite) sublattice are always ferromagnetic (antiferromagnetic). Furthermore we find unusual long-distance decay of the RKKY interaction in BLG. The intralyer RKKY interactions between two magnetic impurities located on the same sublattice, J(AnAn)(R) and T-BnBn (R), decay closely as 1/R-6 and 1/R-2 at large impurity distances respectively, but when they are located on opposite sublattices the RKKY interactions exhibit 1/R-4 decays approximately. In the interlayer case, the RKKY interactions between two magnetic impurities located on the same sublattice show a decay close to 1/R4 at large impurity distances, but if two magnetic impurities be on opposite sublattices the RKKY interactions, J(A1B2) (R) and J(B1A2) (R), decay closely as 1/R-6 and 1/R-2 respectively. Both intra- and interlayer RKKY interactions have anisotropic oscillatory factors which for intralayer case is equal to that for single layer graphene (SLG). Our results at weak and strong interlayer coupling limits reduce to the RKKY interaction of SLG and that of BEG in the two bands approximation respectively. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

Free