Role of temperature-dependent O-p–Fe-d hybridization parameter in the metal-insulator transition of Fe3 O4 : a theoretical study

A D Fauzi1, M A Majidi1 and A Rusydi2,3

1Department of Physics, Faculty of Mathematics and Natural Sciences Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia

2NUSNNI-NanoCore, Department of Physics, Faculty of Science, National University of Singapore, Singapore 117576, Singapore

3Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore

Corresponding author’s email: aziz.majidi@sci.ui.ac.id

Abstract.

 We propose a simple tight-binding based model for Fe3O4 that captures the preference of ferrimagnetic over ferromagnetic spin configuration of the system. Our model is consistent with previous theoretical and experimental studies suggesting that the system is half metallic, in which spin polarized electrons hop only among the Fe B sites. To address the metal insulator transition (MIT) we propose that the strong correlation among electrons, which may also be influenced by the electron-phonon interactions, manifest as the temperature-dependence of the O-p−Fe-d hybridization parameter, particularly Fe-d belonging to one of the Fe B sites (denoted ast (2) FeB−O). By proposing that this parameter increases as the temperature decreases, our density-of-states calculation successfully captures a gap opening at the Fermi level, transforming the system from half metal to insulator. Within this model along with the corresponding choice of parameters and a certain profile of the temperature dependence of t (2) FeB−O, we calculate the resistivity of the system as a function of temperature. Our calculation result reveals the drastic uprising trend of the resistivity profile as the temperature decreases, with the MIT transition temperature located around 100 K, which is in agreement with experimental data.


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