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Computational Modeling of Spintronic Materials

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Editorial15 January 2021
Editorial: Computational Modeling of Spintronic Materials
Xiaotian Wang, Zhenxiang Chengand Gokhan Surucu

Editorial: Computational Modeling of Spintronic Materials

Xiaotian Wang1,*, Zhenxiang Cheng2, Gokhan Surucu3,4,*

1School of Physical Science and Technology, Southwest University, Chongqing 400715, China;

2Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong, Wollongong 2500, Australia;

3Middle East Technical University, Department of Physics, Ankara 06800, Turkey;

4Department of Electric and Energy, Ahi Evran University, Kirsehir 40100, Turkey

E-mail: xiaotianwang@swu.edu.cn (X.W.); g_surucu@yahoo.com (G.S.)

Keywords: first-principle calculations, density-functional theory, material simulation calculations, spintronic materials

Editorial on the Research Topic

Computational Modeling of Spintronic Materials

In research topic “Computational Modeling of Spintronic Materials”, we collected 17 articles dealing with themes as below:

(i)Recent advances of spintronic materials;

(ii)Frontiers in computational modeling of functional materials.

Heulser alloys are famous spintronic materials due to they usually host high Curie temperature and adjustable structures. Zhang et al (Zhang et al. 2020) proposed quaternary Heusler compound CoCrScSn is a half-metal with 100% spin-polarization. Moreover, the elastic constants and half-metallic states under different lattice constants are touched by Zhang et al. Classic Heusler ferromagnets consist of transition-group d-metals and main-group p-elements. As a new direction of Heusler alloy, Wu et al. (Wu et al. 2020) studied a series of all-d-metal Heusler alloys X2MnTi (X = Pd, Pt, Ag, Au, Cu and Ni). X2MnTi alloys are without main-group p-elements. Wu et al. also investigated the competition of the cubic L21 and tetragonal L10 states of these X2MnTi alloys. It is hoped that the possible martensitic transformation of these all-d-metal X2MnTi can be confirmed experimentally.

Half-metals have two spin-directions, one spin channel shows metallic property and the other one features insulating/ semiconducting characters, resulting into 100 % spin-polarization. Half-metals can be used for efficient spin injection in spintronics. Doumi et al (Doumi et al. 2020) proposed that Ca1-xCrxO (x = 0.25, 0.5, 0.75) are half-metals, where the ferromagnetism is mainly coming from the direct exchange splitting instead of the crystal field. Deng et al (Deng et al. 2020) studied the magnetic structure and the Curie temperature of LiMgN with Cu doping, they found that these Cu doped LiMgN systems are dilute magnetic semiconductors with high Curie temperature. More interesting, Li(Mg0.875Cu0.125)N is predicted to be half-metal with a net magnetic moment. Chen et al (Chen et al. 2020) investigated the electronic structures and magnetism of Li1±y(Mg1−xCrx)P (x, y = 0.125). They found that Li(Mg0.875Cr0.125)P magnet is half-metal.

A series of materials co-exhibiting half-metallic state and topological elements are predicted via first-principle calculations. Chang et al (Chang et al. 2020) proposed a rhombohedral type GdMnO3 is a half-metal with multiple Dirac-like band crossing points. Li (Li, 2020) proposed CsCrCl3 ferromagnet P63/mmc structure is a hypothetical half metal and it also belongs to nodal surface materials. Jia et al. (Jia et al. 2020) reported sandwich-like hexagonal VI3 monolayer is a half-metal with Weyl fermion. Moreover, a series of topological semimetals and topological metals are reported in the research topic collection: (i) Zhang and Wang (Zhang and Wang, 2020) found that pure Zr is a topological material with type II nodal line and nodal surface states; (ii) Li and Xia (Li and Xia, 2020) reported that cubic HfN is a topological semimetal with zero-dimensional (0-D) and one-dimensional (1-D) topological elements (TEs); (iii) Li et al. (Li et al., 2020) proposed that tetragonal PtO is a topological material with nodal point and nodal line states; (iv) Xu (Xu 2020) studied the electronic structures and the topological signatures of XPt (X = Sc, Y, and La). XPt are novel systems with rich nodal line and nodal point states. Remarkably, we can observe opened and closed nodal lines, and triply degenerate and Dirac nodal points in these systems; (v) Xu et al. (Xu et al. 2020) predicted that hexagonal Zr3X (X = Al, Ga, In) are metallic systems with high stability and perfect 0-D and 1-D TEs.

Some functional materials and their related physics behaviors are also investigated by first-principles calculations: (i) Ke et al (Ke et al. 2020) performed a band-gap engineering work to study the band structures and band-gap tailoring of C-mono-doped, C-Ge, and C-Sn co-doped GaN nanosheets; (ii) Y2O3:Ce magnetic semiconductor with R-3 group symmetry was identified by Ju et al. (Ju et al. 2020) via CALYPSO, and the structural behaviors, doping site locations and electronic structures of Y2O3:Ce are also studied by Ju et al. via first-principles calculations in details; (iii) Yan et al. (Yan et al. 2020) investigated the reaction pathways of H2 release from the hydrolytic NH3BH3 and examined the catalytic roles of small NiCu clusters; (iv) Chen et al (Chen et al. 2020) built an ultrathin van der Waals Fe3GeTe2/In2Se3 heterostructure and they reported that this heterostructure hosts tunable magnetic anisotropy and Dzyaloshinskii-Moriya Interaction (DMI).

We hope this research topic will attract readers. And we would like to thank all the authors, reviewers and editors who contributed to our research topic.

FUNDING

This study has been funded by the National Natural Science Foundation of China (Grant No. 51801163), and the Fundamental Research Funds for the Central Universities (Grant No. XDJK2019C112).

2,187 views

2 citations

Phase Transition and Electronic Structures of All-d-Metal Heusler-Type X2MnTi Compounds (X = Pd, Pt, Ag, Au, Cu, and Ni)
ORIGINAL RESEARCH
11 December 2020
Phase Transition and Electronic Structures of All-d-Metal Heusler-Type X2MnTi Compounds (X = Pd, Pt, Ag, Au, Cu, and Ni)
Mengxin Wu, 3 more and Xiaotian Wang
In this work, we investigated the phase transition and electronic structures of some newly designed all-d-metal Heusler compounds, X2MnTi (X = Pd, Pt, Ag, Au, Cu and Ni), by means of the first principles. The competition between the XA and L21 structures of these materials was studied, and we found that X2MnTi favors to feature L21 type structure, which is consistent with the well-known site-preference-rule (SPR). Under L21 structure, we have studied the most stable magnetic state of these materials, and we found that the FM state is the most stable due to its lower energy. Through tetragonal deformation, we found that the L21 structure is no longer the most stable structure, and a more stable tetragonal L10 structure appeared. That is, under the tetragonal strain, the material enjoys a tetragonal phase transformation (i.e., from cubic L21 to tetragonal L10 structure). This mechanism of L21-L10 structure transition is discussed in detail based on the calculated density of states. Moreover, we found that the energy difference between the most stable phases of L10 and L21, defined as ΔEM (ΔEM = ECubic-ETetragonal), can be adjusted by the uniform strain. Finally, the phonon spectra of all tetragonal phases X2MnTi (X = Pd, Pt, Ag, Au, Cu and Ni) are exhibited, which provides a powerful evidence for the stability of the tetragonal L10 state. We hope that our research can provide a theoretical guidance for future experimentally investigations.

3,957 views

23 citations

ORIGINAL RESEARCH
8 October 2020
First-Principles Study on the Magnetoelectric and Optical Properties of Novel Magnetic Semiconductor Li(Mg, Cr)P With Decoupled Spin and Charge Doping
Ting Chen, 4 more and Zhimin Wu

2,364 views

5 citations

Tunable Magnetic Anisotropy and Dzyaloshinskii-Moriya Interaction in an Ultrathin van der Waals Fe3GeTe2/In2Se3 Heterostructure
ORIGINAL RESEARCH
25 September 2020
Tunable Magnetic Anisotropy and Dzyaloshinskii-Moriya Interaction in an Ultrathin van der Waals Fe3GeTe2/In2Se3 Heterostructure
Dong Chen, 3 more and Yuanxu Wang

6,452 views

25 citations

ORIGINAL RESEARCH
11 September 2020
Formation of a Key Intermediate Complex Species in Catalytic Hydrolysis of NH3BH3 by Bimetal Clusters: Metal-Dihydride and Boron-Multihydroxy
W. J. Yan, 4 more and H. K. Yuan

3,168 views

7 citations

ORIGINAL RESEARCH
26 August 2020
Weyl Fermions in VI3 Monolayer
Taoyuan Jia, 5 more and Guodong Liu

3,757 views

14 citations

ORIGINAL RESEARCH
14 August 2020
The Tetragonal Monoxide of Platinum: A New Platform for Investigating Nodal-Line and Nodal-Point Semimetallic Behavior
Yang Li, 1 more and Vipul Srivastava

2,915 views

8 citations

ORIGINAL RESEARCH
17 July 2020
Computational Insights Into the Electronic Structure and Magnetic Properties of Rhombohedral Type Half-Metal GdMnO3 With Multiple Dirac-Like Band Crossings
Yu Chang, 4 more and Minquan Kuang

2,576 views

2 citations

ORIGINAL RESEARCH
10 July 2020
Recent Insights Into Electronic Performance, Magnetism and Exchange Splittings in the Cr-substituted CaO
Bendouma Doumi, 2 more and Adlane Sayede
Recent Insights Into Electronic Performance, Magnetism and Exchange Splittings in the Cr-substituted CaO
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.

3,979 views

13 citations

GGA and GGA Plus U Study of Half-Metallic Quaternary Heusler Compound CoCrScSn
ORIGINAL RESEARCH
30 June 2020
GGA and GGA Plus U Study of Half-Metallic Quaternary Heusler Compound CoCrScSn
Chuankun Zhang, 4 more and Guoying Liu
The structural, mechanical, electronic, magnetic, and half-metallic properties of quaternary Heusler compound CoCrScSn are studied using the GGA and GGA+U method based on first-principles calculations. It is found that Type-I structure of CoCrScSn compound is the most stable, and its ground state is ferromagnetic. At the equilibrium lattice constant, the electronic structures obtained by GGA and GGA+U methods indicate that CoCrScSn compound have typical half-metal character. The results of elastic constants and half-metallic robustness show that the mechanical stability and half-metallicity of CoCrScSn can be well maintained in the range of 6.2 to 6.9 Å under GGA and 5.7 to 6.4 Å under GGA+U, respectively. When CoCrScSn compound exhibits half-metallic properties, the total magnetic moment per molecular unit is 4.0 μB, which is in good agreement with the Slater-Pauling rule, and Cr atoms are the main source of molecular magnetic moment. All the aforementioned results indicate that quaternary Heusler compound CoCrScSn would be an ideal candidate in spintronics.

3,962 views

17 citations

The Microstructure and Electronic Properties of Yttrium Oxide Doped With Cerium: A Theoretical Insight
ORIGINAL RESEARCH
28 April 2020
The Microstructure and Electronic Properties of Yttrium Oxide Doped With Cerium: A Theoretical Insight
Meng Ju, 6 more and Yunhong Chen
Trivalent Cerium (Ce3+) doped Yttrium Oxide (Y2O3) host crystal has drawn considerable interest due to its popular optical 5d-4f transition. The outstanding optical properties of Y2O3:Ce system have been demonstrated by previous studies but the microstructures still remain unclear. The lacks of Y2O3:Ce microstructures could constitute a problem to further exploit its potential applications. In this sense, we have comprehensively investigated the structural evolutions of Y2O3:Ce crystals based on the CALYPSO structure search method in conjunction with density functional theory calculations. Our result uncovers a new rhombohedral phase of Y2O3:Ce with R-3 group symmetry. In the host crystal, the Y3+ ion at central site can be naturally replaced by the doped Ce3+, resulting in a perfect cage-like configuration. We find an interesting phase transition that the crystallographic symmetry of Y2O3 changes from cubic to rhombohedral when the impurity Ce3+ is doped into the host crystal. With the nominal concentration of Ce3+ at 3.125%, many metastable structures are also identified due to the different occupying points in the host crystal. The X-ray diffraction patterns of Y2O3:Ce are simulated and the theoretical result is comparable to experimental data, thus demonstrating the validity of the lowest energy structure. The result of phonon dispersions shows that the ground state structure is dynamically stable. The analysis of electronic properties indicate that the Y2O3:Ce possesses a band gap of 4.20 eV which suggests that the incorporation of impurity Ce3+ ion into Y2O3 host crystal leads to an insulator to semiconductor transition. Meanwhile, the strong covalent bonds of O atoms in the crystal, which may greatly contribute to the stability of ground state structure, are evidenced by electron localization function. These obtained results elucidate the structural and bonding characters of Y2O3:Ce and could also provide useful insights for understanding the experimental phenomena.

4,401 views

8 citations