Theoretical exploration of optical response of Fe3O4-reduced graphene oxide nanoparticle system within dynamical mean-field theory

International Symposium on Current Progress in Functional Materials

Majidi, M.A.^1 ; Kusumaatmadja, R.^1 ; Fauzi, A.D.^1 ; Phan, W.Y.^1 ; Taufik, A.^1 ; Saleh, R.^1 ; Rusydi, A.^2,3

Department of Physics, Faculty of Mathematics, Natural Sciences Universitas Indonesia, Kampus UI Depok, Depok

16424, Indonesia^1

NUSNNI-NanoCore, Department of Physics, Faculty of Science, National University of Singapore, Singapore

117576, Singapore^2

Singapore Synchrotron Light Source, National University of Singapore, Singapore

117603, Singapore^3

关键词: Dynamical mean field approximation;    Dynamical mean-field theory;    Fe3O4 nanoparticles;    Nanoparticle systems;    Reduced graphene oxides;    Reduced graphene oxides (RGO);    Repulsive interactions;    Weight percentages;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/188/1/012055/pdf
DOI  :  10.1088/1757-899X/188/1/012055

来源: IOP

【 摘 要 】

We theoretically investigate the optical conductivity and its related optical response of Fe3O4-reduced graphene oxide (rGO) nanoparticle system. Experimental data of magnetization of the Fe3O4-rGO nanoparticle system have shown that the saturation magnetization can be enhanced by controlling the rGO content with the maximum enhancement reached at the optimal rGO content of about 5 weight percentage. We hypothesize that the magnetization enhancement is due to spin-flipping of Fe ions at tetrahedral sites induced by oxygen vacancies at the Fe3O4nanoparticle boundaries. These oxygen vacancies are formed due to adsorption of oxygen atoms by rGO flakes around the Fe3O4nanoparticle. In this study, we aim to explore the implications of this effect to the optical response of the system as a function of the rGO content. Our model incorporates Hubbard-repulsive interactions between electrons occupying the e g orbitals of Fe3+and Heisenberg-like interactions between electron spins and spins of Fe3+ions. We treat the relevant interactions within mean-field and dynamical mean-field approximations. Our results are to be compared with the existing experimental reflectance data of Fe3O4nanoparticle system.