First-principles calculations of GaN:Gd nanowires: Carbon-dopants-induced room-temperature ferromagnetism

Ruikuan Xie,Yuan Liang,Yan Huang,Xiaoshuang Chen,Yijie Zeng,Huaizhong Xing

doi:10.1063/1.5001473

Ruikuan Xie, Yuan Liang + Show 4 more

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https://doi.org/10.1063/1.5001473

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Abstract

First-principle calculations of the electronic structure and magnetic interaction of C-Gd co-doped GaN nanowires have been performed. The room-temperature ferromagnetism in GaN:Gd nanowires is observed after the substitution of N atoms by C atoms. A p-d coupling is considered as the reason of the observed ferromagnetism. The striking feature is that such coupling is effected greatly by the position where the C atoms dope in. As the C-Gd distance increases this coupling decreases and the system won’t gain enough energy to stabilize the ferromagnetism.

Highlights

Compared with conventional semiconductor devices, spintronic devices have the potential advantages of nonvolatility, increased data processing speed, decreased electric power consumption, and increased integration densities owing to the participation of the spin freedom of electrons.[4]
The results clearly tell us that only those C dopants which are adjacent to Gd atoms can help to stabilize the FM state
We investigated the nanowires with two Gd dopants and so we could compare the stability of FM and AFM states which Kaleemullah didn’t do in their research

Summary

Introduction

Over the past several years, semiconductor spintronics has been studied extensively for it offering a possibility that hybrid devices that possess semiconducting and spin properties could perform all the three operations, logic, communications and storage, within the same materials technology.[1,2,3] Compared with conventional semiconductor devices, spintronic devices have the potential advantages of nonvolatility, increased data processing speed, decreased electric power consumption, and increased integration densities owing to the participation of the spin freedom of electrons.[4]. One of the main targets of realizing fabricating spintronics is introducing magnetic functionality to nonmagnetic semiconductors at room temperature. Gd-doped GaN is one of the most controversial owing to its room-temperature ferromagnetism.[6,7,8,9,10] Ga0.94Gd0.6N layer was found a Curie temperature (Tc) higher than 400K.6. Dhar et al found room-temperature ferromagnetism in Gd-doped GaN and colossal magnetic moment of Gd with a low Gd concentration.[8] They pointed out that the ferromagnetic (FM) coupling of this system could not be explained by the direct, double, or super-exchange between Gd atoms because of the long distance

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