Computational Modeling of Spintronic Materials

Sürücü, Gökhan
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 L21and tetragonal L10states 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 behaviors, resulting in 100% spin-polarization. Also, 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 interestingly, 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-principles calculations. Chang et al. (Chang et al., 2020) proposed a rhombohedral type GdMnO3is a half-metal with multiple Dirac-like band crossing points. Li (Li, 2020) proposed CsCrCl3ferromagnet 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 VI3monolayer is a half-metal with Weyl fermions. Moreover, a series of topological semimetals and topological metals are reported in the research topic collection: 1) Zhang and Wang (Zhang and Wang, 2020) found that pure Zr is a topological material with type II nodal line and nodal surface states; 2) 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); 3) Li et al. (Li et al., 2020) proposed that tetragonal PtO is a topological material with nodal point and nodal line states; 4) Xu (Xu, 2020) studied the electronic structures and the topological signatures of XPt (X= Sc, Y, and La) via first-principles calculations. XPt (X= Sc, Y and La) materials are proposed to be 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; 5) 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: 1) 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; 2) 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 as well as electronic structures of Y2O3:Ce are also studied by Ju et al. via first-principles calculations in details; 3) Yan et al. (Yan et al., 2020) investigated the reaction pathways of H2release from the hydrolytic NH3BH3and examined the catalytic roles of small NiCu clusters; 4) Chen et al. (Chen et al., 2020) built an ultrathin van der Waals Fe3GeTe2/In2Se3heterostructure 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.


Hybrid wavelet-neural network models for time series data
Kılıç, Deniz Kenan; Uğur, Ömür; Department of Financial Mathematics (2021-3-3)
The thesis aims to combine wavelet theory with nonlinear models, particularly neural networks, to find an appropriate time series model structure. Data like financial time series are nonstationary, noisy, and chaotic. Therefore using wavelet analysis helps better modeling in the sense of both frequency and time. S&P500 (∧GSPC) and NASDAQ (∧ IXIC) data are divided into several components by using multiresolution analysis (MRA). Subsequently, each part is modeled by using a suitable neural network structure. ...
Stochastic modelling of biochemical networks and inference of model parameters
Purutçuoğlu Gazi, Vilda (Springer International Publishing, 2018-04-01)
The research and review papers presented in this volume provide an overview of the main issues, findings, and open questions in cutting-edge research on the fields of modeling, optimization and dynamics and their applications to biology, economics, energy, finance, industry, physics and psychology. Given the scientific relevance of the innovative applications and emerging issues they address, the contributions to this volume, written by some of the world’s leading experts in mathematics, economics and oth...
Numerical integration of a class of 3d plastic-damage concrete models and condensation of 3d stress-strain relations for use in beam finite elements
Sarıtaş, Afşin (Elsevier BV, 2009-10-01)
This paper presents a method for the integration of a class of plastic-damage material models. The integration of the evolution equations results in a nonlinear problem, which is linearized and solved with the Newton-Raphson method using a sub-stepping strategy. The consistent tangent matrix can be formulated either in terms of the stress components in a general reference system or in terms of the principal stress and strain components with the former then transformed to the general reference system. In ord...
Conceptual data modeling of multimedia database applications
Aygun, S; Yazıcı, Adnan; Arica, N (1998-08-07)
In this paper, we present a conceptual data model for multimedia database applications based on ExIFO(2) model. The ExIFO(2) data model is chosen as the conceptual model since it handles both complex objects along with their uncertain and imprecise properties. We enhanced this conceptual model in order to meet the multimedia data requirements. In addition to uncertain and imprecise information, we present a way of handling relationships among objects of multimedia database applications. Events that might be...
Simulation of dynamical refractive index change in on-chip optical devices
Aslan, Anıl; Kocaman, Serdar; Department of Electrical and Electronics Engineering (2019)
Theoretical modeling and numerical verification are essential in integrated photonics for designing optimized structures as well as interpretation of the experimental results. In this thesis, a dynamically changing refractive index modification for the Finite Difference Time Domain (FDTD) method is proposed, implemented with C++ and results are compared with recent experimental studies. The proposed method is based on the idea of the time-domain simulation of the non-stationary objects while satisfying the ...
Citation Formats
G. Sürücü, Computational Modeling of Spintronic Materials. 2021.