Recent Insights Into Electronic Performance, Magnetism and Exchange Splittings in the Cr-substituted CaO.

Abdelkader Tadjer,Adlane Sayede,Allel Mokaddem,Bendouma Doumi

doi:10.3389/fchem.2020.00526

Abstract

The first-principles computations of density functional theory are employed to characterize the structural properties, electronic structures, and ferromagnetism induced by Cr impurities in Ca1-xCrxO compounds at concentrations x = 0. 25, 0.5, and 0.75. The dynamic stability is performed by the phonon spectra calculations. The structural parameters are computed by using Wu-Cohen generalized gradient approximation, while the electronic and magnetic properties are determined by the accurate Tran–Blaha-modified Becke–Johnson exchange potential. The crystal field, direct and indirect exchange splittings were investigated to determine the origin and stability of ferromagnetic state configuration. The Ca1-xCrxO systems have right half-metallicities, which are verified by the spin polarization of 100% and the integer values of total magnetic moments. The Ca0.75Cr0.25O, Ca0.5Cr0.5O, and Ca0.25Cr0.75O are half-metallic ferromagnetic with flip-gaps of 1.495, 0.888, and 0.218 eV, respectively. Therefore, the Ca1-xCrxO materials are suitable candidates for possible applications of spin-injection in future semiconductors spintronics.

Highlights

In recent years, the exploitation of new materials for technological development has become an attractive area of research for the scientific community
The ferromagnetism in C-doped CaO is explained by the exchange coupling constants, where it is induced by the strong hybridization between 2p states of carbon and 2p states of oxygen (An Dinh et al, 2006)
Crystal Structures The calcium oxide CaO is known as a wide-band gap II–VI semiconductor, crystallizing in rock-salt NaCl (B1) structure at ambient conditions (Doll et al, 1996; Mishra et al, 2012)

Summary

Introduction

The exploitation of new materials for technological development has become an attractive area of research for the scientific community. The diluted magnetic semiconductors (DMSs) are obtained from the III–V, II–VI, or IV–VI semiconductors doped with magnetic elements, inducing changes in their structural, electronic, and magnetic properties, which are related to the concentration of magnetic impurities These materials have received a lot of attention for scientific research because they are promising. Alkaline earth chalcogenides are important materials with a wide technological application ranging from catalysis to microelectronics as well as in the area of electro- and photoluminescent devices (Hakamata et al, 2005; Speziale et al, 2006; Murtaza et al, 2014) Among these compounds, the CaX (X = O, S, Se) has a closed-shell ionic environment, crystallizing in the rock-salt NaCl-type (B1) structure at ambient conditions (Doll et al, 1996; Mishra et al, 2012). Kemmochi et al (2005) have found that the stability of ferromagnetic state in the C-doped CaO is originated from the Zener’s double-exchange mechanism

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Conclusion