A STUDY ON MAGNETIC PROPERTIES OF Cu-DOPED GaN

2011 ◽  
Vol 25 (17) ◽  
pp. 1457-1472 ◽  
Author(s):  
LI-BIN SHI ◽  
HONG-KUAN YUAN
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Exchange Coupling ◽  
Density Functional ◽  
Coupling Model ◽  
Weak Ferromagnetism ◽  
First Principle ◽  
Theoretical Understanding ◽  
Functional Theory ◽  
Carbon Impurities

Using the first principle method based on density functional theory (DFT), we have studied the magnetic properties in Cu -doped GaN . The result shows that Cu in GaN exhibits spontaneous spin polarization. The energies of ferromagnetism (FM) and antiferromagnetism (AFM) coupling are calculated for eleven different configurations. It is found that Cu -doped GaN has a FM ground state. It is not found that Cu atoms have a clear clustering tendency. Origin of FM properties is also explained by energy level coupling model. In the paper, we also investigate the effect of nitrogen, gallium vacancies and carbon impurities on magnetic properties. The results show that nitrogen, gallium vacancies and carbon impurities cannot enhance FM coupling of Cu -doped GaN . In addition, exchange coupling coefficient and Curie temperature are also investigated. The Cu -doped GaN is proposed to be weak ferromagnetism according to Curie temperature and magnetic moment. The present study provides some theoretical understanding for the experiments on Cu -doped GaN .

scholarly journals Electronic and Magnetic Properties of Bulk and Monolayer CrSi2: A First-Principle Study

2018 ◽  
Vol 8 (10) ◽  
pp. 1885 ◽  
Author(s):  
Shaobo Chen ◽  
Ying Chen ◽  
Wanjun Yan ◽  
Shiyun Zhou ◽  
Xinmao Qin ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Phonon Dispersion ◽  
First Principle ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Phonon Dispersion Curves ◽  
Electronic And Magnetic Properties ◽  
Quantum Size ◽  
Spin Polarized

We investigated the electronic and magnetic properties of bulk and monolayer CrSi2 using first-principle methods based on spin-polarized density functional theory. The phonon dispersion, electronic structures, and magnetism of bulk and monolayer CrSi2 were scientifically studied. Calculated phonon dispersion curves indicated that both bulk and monolayer CrSi2 were structurally stable. Our calculations revealed that bulk CrSi2 was an indirect gap nonmagnetic semiconductor, with 0.376 eV band gap. However, monolayer CrSi2 had metallic and ferromagnetic (FM) characters. Both surface and confinement effects played an important role in the metallic behavior of monolayer CrSi2. In addition, we also calculated the magnetic moment of unit cell of 2D multilayer CrSi2 nanosheets with different layers. The results showed that magnetism of CrSi2 nanosheets was attributed to band energy between layers, quantum size, and surface effects.

Structural, electronic and magnetic properties of (N, C)-codoped ZnO nanotube: First principles study

2015 ◽  
Vol 26 (11) ◽  
pp. 1550130 ◽  
Author(s):  
Amirhosein Esmailian ◽  
Masoud Shahrokhi ◽  
Faramarz Kanjouri
Keyword(s):  
Magnetic Properties ◽  
First Principles ◽  
Density Functional ◽  
Nearest Neighbor ◽  
First Principle ◽  
Functional Theory ◽  
Impurity Atoms ◽  
Zno Nanotube ◽  
The Density Functional Theory ◽  
Zno Nanotubes

We have studied the electronic structure and magnetic properties of Nitrogen and Carbon codoped ZnO (5,0) single-walled zigzag nanotube using first-principle calculations based on the density functional theory. We performed our calculations for N - and C - codoping ZnO nanotube in two different configurations. For the first configuration in which the two impurity atoms ( N or C ) are on first nearest-neighbor sites in the plane of codoping, our calculation predicts that the N - and C -codoped ZnO nanotubes are antiferromagnetic material with no net magnetization. On the other hand, it is found that for the configuration in which the two impurity atoms are next nearest-neighbors, a spin polarization results in a magnetic moment in the N - and C -codoped ZnO nanotubes.

Ab initio study of magnetic properties of Fe-Mn-Al Heusler alloys

2013 ◽  
Vol 1581 ◽  
Author(s):  
Vladimir V. Sokolovskiy ◽  
Vasiliy D. Buchelnikov ◽  
Mikhail A. Zagrebin ◽  
Sergey V. Taskaev ◽  
Vladimir V. Khovaylo ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Density Functional ◽  
Heusler Alloys ◽  
Exchange Interactions ◽  
Ferromagnetic Coupling ◽  
Magnetic Exchange ◽  
Functional Theory ◽  
Spin Polarized ◽  
Curie Temperatures

ABSTRACTDensity functional theory (DFT) based on the spin-polarized relativistic Korringa-Kohn-Rostoker (SPR-KKR) method is used to investigate the magnetic properties of nonstoichiometric Fe2+xMn1-xAl Heusler alloys, where 0 ≤ x ≤ 0.9. The composition dependences of the magnetic exchange couplings and the Curie temperature for the cubic L21 phase are obtained. Our simulations have shown that the Fe-Fe nearest neighbors present a strong ferromagnetic coupling. Moreover, these exchange interactions are larger than other interactions. The substitution of Mn by Fe in Fe2+xMn1-xAl (0 ≤ x ≤ 0.9) leads to an increase in the Curie temperature. This tendency and the values of Curie temperatures are in agreement with the experimental results for Fe2+xMn1-xAl (x = 0, and 0.1). The highest Curie temperature was observed for the Fe-richer alloy.

First-principle investigation on electronic structures and magnetic properties of EuNbO3 phases

2019 ◽  
Vol 85 (1) ◽  
pp. 10601 ◽  
Author(s):  
Sheng Xu ◽  
Yanni Gu ◽  
Xiaoli Zhang ◽  
Xiaoshan Wu
Keyword(s):  
Magnetic Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Structural Parameters ◽  
First Principle ◽  
Orthorhombic Space Group ◽  
Functional Theory ◽  
Ferromagnetic Metals ◽  
Cubic Phases ◽  
The Eu

Recently, structure phase transitions were experimentally found in europium niobate (EuNbO3). Here, we present a density-functional theory (DFT) investigation of structural, electronic and magnetic properties of the experimentally observed three phases of EuNbO3: orthorhombic (space group Imma), tetragonal (I4/mcm) and cubic (Pmm). The calculated structural parameters and magnetic properties of the ground state are in agreement with available experimental results. The ground states of the orthorhombic and cubic phases are ferromagnetic metals and the tetragonal phase is predicted as an antiferromagnetic metal. Besides, the Eu atom has the magnetic moment of 6.9 μB/atom in the EuNbO3 phases. The present study provides a theoretical approach to understand EuNbO3 in its different phases.

Enhanced ferromagnetic properties of Cu doped two-dimensional GaN monolayer

2015 ◽  
Vol 26 (01) ◽  
pp. 1550009 ◽  
Author(s):  
Fayyaz Hussain ◽  
Y. Q. Cai ◽  
M. Junaid Iqbal Khan ◽  
Muhammad Imran ◽  
Muhammad Rashid ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Density Functional ◽  
Magnetic Coupling ◽  
First Principle ◽  
Two Dimensional ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Cu Dopant

We demonstrate enhanced ferromagnetism in copper doped two-dimensional GaN monolayer ( GaN -ML). Our first principle calculation based on density functional theory predicted that nonmagnetic Cu -dopant with concentration of 6.25% to be ferromagnetic (FM) in 2D GaN layer which carries a magnetic moment of 2.0 μB per Cu atom and it is found to be long range magnetic coupling among the Cu -dopant. The Cu-dopant in 2D GaN -ML which can be explained in terms of p-d hybridization at Curie temperature and this dopant prefer the FM behavior in 2D GaN layer. Hence Cu doped 2D GaN layer shows strong magnetic properties so that it is a promising material in the field of spintronics.

Electronic and magnetic properties of Fe-doped GaN: first-principle calculations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Adam S. Abdalla ◽  
Muhammad Sheraz Khan ◽  
Suliman Alameen ◽  
Mohamed Hassan Eisa ◽  
Osamah Aldaghri
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Density Functional ◽  
Magnetic Semiconductor ◽  
Magnetic Coupling ◽  
First Principle ◽  
Functional Theory ◽  
Electronic And Magnetic Properties ◽  
First Principle Calculations ◽  
Co Doped

Abstract We have systematically studied the effect of Fe co-doped on electronic and magnetic properties of wurtzite gallium nitride (GaN) based on the framework of density functional theory (DFT). It is found that GaN doped with Fe at Ga site is more stable than that at N-site. We calculate the electronic structure of pure and single Fe doped GaN within GGA and GGA + U method and find that Fe doped GaN is a magnetic semiconductor with the total magnetization of 5μ B . The magnetic coupling between Fe spins in Fe-doped GaN is an antiferromagnetic (AFM) under the super-exchange mechanism.

scholarly journals Electronic and Magnetic Properties of Stone–Wales Defected Graphene Decorated with the Half-Metallocene of M (M = Fe, Co, Ni): A First Principle Study

Nanomaterials ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 552 ◽  
Author(s):  
Kefeng Xie ◽  
Qiangqiang Jia ◽  
Xiangtai Zhang ◽  
Li Fu ◽  
Guohu Zhao
Keyword(s):  
Magnetic Properties ◽  
Band Structure ◽  
Metal Ion ◽  
Density Functional ◽  
Electronic Devices ◽  
First Principle ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Potential Applications ◽  
Defected Graphene

The geometrical, electronic structure, and magnetic properties of the half-metallocene of M (M = Fe, Co, Ni) adsorbed on Stone–Wales defected graphene (SWG) were studied using the density functional theory (DFT), aiming to tune the band structure of SWG. The introduction of cyclopentadienyl (Cp) and half-metallocene strongly affected the band structure of SWG. The magnetic properties of the complex systems originated from the 3D orbitals of M (M = Fe, Co, Ni), the molecular orbital of Cp, and SWG. This phenomenon was different from that found in a previous study, which was due to metal ion-induced sandwich complexes. The results have potential applications in the design of electronic devices based on SWG.

scholarly journals Tuning Electronic Structure and Magnetic Properties of Flat Stanene by Hydrogenation and Al/P Doping: A First Principle DFT Study

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 47
Author(s):  
Mauludi Ariesto Pamungkas ◽  
Vinsa Kharisma Rofiqo Sari ◽  
Irwansyah ◽  
Setiawan Ade Putra ◽  
Abdurrouf ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
Density Functional ◽  
Magnetic Semiconductor ◽  
Ferromagnetic Material ◽  
First Principle ◽  
Two Dimensional ◽  
Hollow Site ◽  
Functional Theory ◽  
Shed Light

A Stanene, is a two-dimensional material composed of tin atoms arranged in a single hexagonal layer, in a manner similar to graphene. First principle studies based on density functional theory were performed to investigate the effects of hydrogenation and Al/P doping on electronic structure and magnetic properties of stanene. Hydrogenation opens the bandgap of stanene and changes it from nonmagnetic to the ferromagnetic material through H 1s states and Sn 5p states hybridization. Al/P atom at hollow site prevent electrons of adjacent Sn atoms to connect so that inducing unpaired electrons. The combination of hydrogenation and Al/P doping increases its magnetization. The sequence based on its magnetic moment from small to large is as follows: pure stanene, Al-doped stanene, P-doped stanene, hydrogenated stanene, Al-doped hydrogenated stanene, and P-doped hydrogenated stanene. The controllable transformation from nonmagnetic metallic to a magnetic semiconductor is a key requirement for materials to be used as spintronic materials. Thus, these results may shed light on designing the stanene-based electronic and spintronics materials.

Assessing the Calculation of Exchange Coupling Constants and Spin Crossover Gaps Using the Approximate Projection Model to Improve Density Function Calculations

2019 ◽  
Author(s):  
Xianghai Sheng ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Density Functional Theory ◽  
Exchange Coupling ◽  
Density Functional ◽  
Spin Crossover ◽  
Coupling Constants ◽  
Spin Projection ◽  
Coupling Constant ◽  
Projection Model ◽  
Functional Theory

This work evaluates the quality of exchange coupling constant and spin crossover gap calculations using density functional theory corrected by the Approximate Projection model. Results show that improvements using the Approximate Projection model range from modest to significant. This study demonstrates that, at least for the class of systems examined here, spin-projection generally improves the quality of density functional theory calculations of J-coupling constants and spin crossover gaps. Furthermore, it is shown that spin-projection can be important for both geometry optimization and energy evaluations. The Approximate Project model provides an affordable and practical approach for effectively correcting spin-contamination errors in molecular exchange coupling constant and spin crossover gap calculations.

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