Perovskite R{\bar 3}c phase AgCuF3: multiple Dirac cones, 100% spin polarization and its thermodynamic properties

2019 ◽  
Vol 75 (3) ◽  
pp. 354-360
Author(s):  
Minquan Kuang ◽  
Tingzhou Li ◽  
Zhenxiang Cheng ◽  
Houari Khachai ◽  
R. Khenata ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Spin Polarization ◽  
Spin Orbit Coupling ◽  
Dynamic Simulations ◽  
Metallic Behavior ◽  
Half Metallic ◽  
Spin Polarized ◽  
Different Temperatures ◽  
The Stability ◽  
Thermal Volume Expansion

Very recently, experimentally synthesized R{\bar 3}c phase LaCuO3 was studied by Zhang, Jiao, Kou, Liao & Du [J. Mater. Chem. C (2018), 6, 6132–6137], and they found that this material exhibits multiple Dirac cones in its non-spin-polarized electronic structure. Motivated by this study, the focus here is on a new R{\bar 3}c phase material, AgCuF3, which has a combination of multiple Dirac cones and 100% spin polarization properties. Compared to the non-spin-polarized system LaCuO3, the spin-polarized Dirac behavior in AgCuF3 is intrinsic. The effects of on-site Coulomb interaction, uniform strain and spin–orbit coupling were added to examine the stability of its multiple Dirac cones and half-metallic behavior. Moreover, the thermodynamic properties under different temperatures and pressures were investigated, including the normalized volume, thermal volume expansion coefficient, heat capacity at constant volume and Debye temperature. The thermal stability and the phase stability of this material were also studied via ab initio molecular dynamic simulations and the formation energy of the material, respectively.

Investigation of the structural, electronic, elastic and thermodynamic properties of Curium Monopnictides: An ab initio study

2017 ◽  
Vol 31 (30) ◽  
pp. 1750226 ◽  
Author(s):  
H. Baaziz ◽  
Dj. Guendouz ◽  
Z. Charifi ◽  
S. Akbudak ◽  
G. Uğur ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
Density Functional ◽  
Local Density ◽  
Structural Parameters ◽  
Structural Phase ◽  
Full Potential ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Spin Polarized

The structural, electronic, elastic and thermodynamic properties of Curium Monopnictides CmX (X = N, P, As, Sb and Bi) are investigated using first-principles calculations based on the density functional theory (DFT) and full potential linearized augmented plane wave (FP-LAPW) method under ambient condition and high pressure. The exchange-correlation term is treated using two approximations spin-polarized local density approximation (LSDA) and spin-polarized generalized gradient approximation generalized (GGA). The structural parameters such as the equilibrium lattice parameters, bulk modulus and the total energies are calculated in two phases: namely NaCl (B1) and CsCl (B2). The obtained results are compared with the previous theoretical and experimental results. A structural phase transition from B1 phase to B2 phase for Curium pnictides has been obtained. The highest transition pressure is 122 GPa for CmN and the lowest one is 10.0 GPa for CmBi compound. The electronic properties show that these materials exhibit half-metallic behavior in both phases. The magnetic moment is found to be around 7.0 [Formula: see text]B. The mechanical properties of CmX (X = N, P, As, Sb and Bi) are predicted from the calculated elastic constants. Our calculated results are in good agreement with the theoretical results in literature. The effect of pressure and temperature on the thermodynamic properties like the cell volume, bulk modulus and the specific heats C[Formula: see text] and C[Formula: see text], the entropy [Formula: see text] and the Grüneisen parameter [Formula: see text] have been foreseen at expanded pressure and temperature ranges.

DFT-Based Study on Electronic, Magnetic and Thermodynamic Properties of HoMnO3: A Half-Metallic Material with Nearly Linear Band Crosses

SPIN ◽  
2019 ◽  
Vol 09 (03) ◽  
pp. 1950017
Author(s):  
Ting-Zhou Li ◽  
R. Khenata ◽  
Houari Khachai ◽  
Xiaotian Wang
Keyword(s):  
Thermodynamic Properties ◽  
Density Functional ◽  
Hole Doping ◽  
Spin Orbit Coupling ◽  
Functional Theory ◽  
Metallic Material ◽  
Half Metallic ◽  
Spintronic Devices ◽  
Linear Band ◽  
Perovskite Type

A novel half-metallic family of materials, the multiple Dirac cones half-metals, has received considerable interest from researchers. Benefiting from its novel electronic structure, they are promising candidates for ultra-performance spintronic devices. In this paper, we propose a new half-metallic material, perovskite-type [Formula: see text] HoMnO3, which possesses similar Dirac-like multiple linear band crosses. We investigated its electronic, magnetic and thermodynamic properties in detail on the basis of density functional theory. The excellent band structures are robust enough against spin-orbit coupling and electron and hole doping. Through calculations, we confirmed its multi-aspect stability. Based on the current study, we confirm that HoMnO3 has potential for next-generation spintronic applications.

scholarly journals A Landau-Ginzburg Description of Sb Overlayers

2001 ◽  
Vol 674 ◽  
Author(s):  
R. Skomski ◽  
T. Komesu ◽  
H.-K. Jeong ◽  
C. N. Borca ◽  
P. A. Dowben ◽  
...  
Keyword(s):  
Spin Polarization ◽  
Heusler Alloy ◽  
Function Approximation ◽  
Gaussian Approximation ◽  
Temperature Dependent ◽  
Half Metallic ◽  
Spin Polarized ◽  
Spin Excitations ◽  
Injection Depth ◽  
Inverse Photoemission Spectroscopy

ABSTRACTThe spin polarization of Sb overlayers on the semi-Heusler alloy NiMnSb is investigated in terms of the Landau-Ginzburg approach. The half-metallic semi-Heusler alloy NiMnSb acts as a ferromagnetic perturbation and induces a spin polarization in the semimetallic Sb overlayer. Using a Gaussian approximation, the propagation of the spin perturbation in the overlayer is calculated. The results are compared with spin-polarized inverse photoemission spectroscopy (SPIPES) results and with recent spin-dependent envelope-function approximation (SDEFA) predictions. The Landau-Ginzburg parameters are both band-structure and temperature dependent, and it is argued that thermal spin excitations lead to an injection depth decreasing as 1//T law at high temperatures.

Spin polarization of polaron in quasi-one dimensional organic system

2015 ◽  
Vol 29 (02) ◽  
pp. 1450266 ◽  
Author(s):  
Hong Jiang ◽  
Chao Zhang ◽  
Xuening Hu ◽  
Guichao Hu ◽  
Shijie Xie
Keyword(s):  
Spin Polarization ◽  
Organic Materials ◽  
Orbit Coupling ◽  
Electron Interaction ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Organic System ◽  
Electron Phonon Coupling ◽  
Spin Polarized ◽  
Ssh Model

The spin polarization of polarons in quasi-1D organic materials has been investigated by using the extended Su–Schrieffer–Heeger (SSH) model with spin-orbit coupling. Results show that the polaron is partly spin polarized, and that the electron–electron interaction and spin-orbit coupling compete with each other during the formation of spin polarization. The dependence of spin polarization on electron–phonon coupling is also revealed. Our results demonstrate that spin polarization is well correlated with polaron localization, thus providing useful guidance for exploring magnetic effects in organic materials.

Thermodynamic stability, half-metallic and optical nature of graphene-like Mn2 ZrZ (Z = Ge, Si): Ab initio study

2018 ◽  
Vol 32 (29) ◽  
pp. 1850324
Author(s):  
Arash Anjami ◽  
Arash Boochani ◽  
Seyed Mohammad Elahi ◽  
Hosein Akbari
Keyword(s):  
Density Functional ◽  
Ultra Violet ◽  
Refraction Index ◽  
Infrared Region ◽  
Full Potential ◽  
Metallic Behavior ◽  
Half Metallic ◽  
Optical Responses ◽  
Spin Polarized ◽  
Thermodynamic Phase

Half-metallic, optical and thermodynamic phase diagrams of two-dimensional Mn2ZrZ (Z = Ge, Si) have been calculated by density functional theory (DFT) framework with full-potential linear augmented plane-wave (FP-LAPW) method. The spin-polarized electronic computations show that these layers have metallic behavior with a spin polarization less than 100%. It is observed that with increasing thickness of the layers, both the thermodynamic and energy stabilities increased, and the graphene-like layers of Mn2ZrGe with a thickness of 7.6955 Å and Mn2ZrSi with a thickness of 7.551 Å are completely stable thermodynamically. The optical responses of Mn2ZrZ (Z = Ge, Si) have anisotropy at infrared region versus the optical direction and have high metallic nature in this optical range. The plasmonic frequencies have occurred after the visible edge and the refraction index becomes lower than one after the ultra-violet edge.

In Search for Novel Sn2Co3S2-based Half-metal Ferromagnets

2014 ◽  
Vol 69 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Florian Pielnhofer ◽  
Amadeus Samuel Tragl ◽  
Jan Rothballer ◽  
Richard Weihrich
Keyword(s):  
Density Functional ◽  
Substitution Effects ◽  
The Novel ◽  
Functional Theory ◽  
Half Metallic ◽  
Half Metal ◽  
Spin Polarized ◽  
Densities Of States ◽  
Metallic Ferromagnet ◽  
The Stability

Substitution effects on magnetism of shandite-type compounds have been studied by density functional theory. The decrease of the Fermi level in the novel half-metallic ferromagnet Sn2Co3S2 to higher maxima of the density of states was modeled for substitutions on the Co site by the 3d metals Fe, Mn and Cr due to a rigid band scheme. Spin-polarized energy hyper surfaces and densities of states are calculated for Sn2Co3S2, and experimentally not yet known Sn2Fe3S2, Sn2Mn3S2 and Sn2Cr3S2 with shandite-type structure. The stability of half-metallic ferromagnetic characteristics, Slater-Pauling behavior, and alternative metastable spin states are discussed.

scholarly journals Tunable spin-valley coupling in layered polar Dirac metals

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Masaki Kondo ◽  
Masayuki Ochi ◽  
Tatsuhiro Kojima ◽  
Ryosuke Kurihara ◽  
Daiki Sekine ◽  
...  
Keyword(s):  
Transition Metal ◽  
Spin Polarization ◽  
Transition Metal Dichalcogenides ◽  
Spin Orbit Coupling ◽  
Dirac Fermions ◽  
Fermi Surfaces ◽  
Haas Oscillation ◽  
Spin Polarized ◽  
Metal Dichalcogenides ◽  
Inversion Asymmetry

AbstractIn non-centrosymmetric metals, spin-orbit coupling induces momentum-dependent spin polarization at the Fermi surfaces. This is exemplified by the valley-contrasting spin polarization in monolayer transition metal dichalcogenides with in-plane inversion asymmetry. However, the valley configuration of massive Dirac fermions in transition metal dichalcogenides is fixed by the graphene-like structure, which limits the variety of spin-valley coupling. Here, we show that the layered polar metal BaMnX2 (X = Bi, Sb) hosts tunable spin-valley-coupled Dirac fermions, which originate from the distorted X square net with in-plane lattice polarization. We found that BaMnBi2 has approximately one-tenth the lattice distortion of BaMnSb2, from which a different configuration of spin-polarized Dirac valleys is theoretically predicted. This was experimentally observed as a clear difference in the Shubnikov-de Haas oscillation at high fields between the two materials. The chemically tunable spin-valley coupling in BaMnX2 makes it a promising material for various spin-valleytronic devices.

scholarly journals Electronic and Magnetic Properties of Rare-Earth Metals Doped ZnO Monolayer

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Changlong Tan ◽  
Dianshuang Xu ◽  
Kun Zhang ◽  
Xiaohua Tian ◽  
Wei Cai
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Spin Polarization ◽  
Rare Earth Metals ◽  
Metallic Behavior ◽  
Half Metallic ◽  
Electronic And Magnetic Properties ◽  
Efficient Route ◽  
Doped Zno ◽  
Dy Doping

The structural, electronic, and magnetic properties of rare-earth metals doped ZnO monolayer have been investigated using the first-principles calculations. The induced spin polarization is confirmed for Ce, Eu, Gd, and Dy dopings while the induced spin polarization is negligible for Y doping. The localizedfstates of rare-earth atoms respond to the introduction of a magnetic moment. ZnO monolayer undergoes transition from semiconductor to metal in the presence of Y, Ce, Gd, and Dy doping. More interestingly, Eu doped ZnO monolayer exhibits half-metallic behavior. Our result demonstrates that the RE-doping is an efficient route to modify the magnetic and electronic properties in ZnO monolayer.

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