SILICON-BASED HALF-METAL: METAL-ENCAPSULATED SILICON NANOTUBE

NANO ◽  
2007 ◽  
Vol 02 (02) ◽  
pp. 109-114 ◽  
Author(s):  
J. BAI ◽  
X. C. ZENG
Keyword(s):  
First Principles ◽  
First Principles Calculation ◽  
Electronic Band ◽  
Half Metallic ◽  
Half Metal ◽  
Silicon Nanostructure ◽  
Metal Metal ◽  
Silicon Based ◽  
Electronic Band Structures ◽  
Silicon Nanotube

We performed first-principles calculation to show that a host–guest silicon nanostructure can exhibit half-metallic properties, wherein the host is a single-walled hexagonal silicon nanotube while the guest is a hybrid atomic chain of Mn and Co (encapsulated in the host nanotube). The calculated electronic band structures indicate that the Fermi level intersects only in the spin-up band, whereas the spin-down band exhibits semiconducting characteristics.

Cation ordering induced semiconductor to half metal transition in La2NiCrO6

RSC Advances ◽  
2015 ◽  
Vol 5 (63) ◽  
pp. 50913-50918 ◽  
Author(s):  
Jing Wang ◽  
Xiangfeng Hao ◽  
Yuanhui Xu ◽  
Zhiping Li ◽  
Ningning Zu ◽  
...  
Keyword(s):  
First Principles ◽  
First Principles Calculation ◽  
Cation Ordering ◽  
Half Metallic ◽  
Half Metal

La2NiCrO6, previously proposed to be a candidate of half metallic antiferromagnetism, is revisited using the first-principles calculation.

Structures and Electronic Properties of Graphene with Vacancy Defects

2014 ◽  
Vol 1658 ◽  
Author(s):  
J. Sugimoto ◽  
K. Shintani
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
First Principles Calculation ◽  
Band Structures ◽  
Electronic Band ◽  
Vacancy Defects ◽  
Electronic Band Structures ◽  
Formation Energies

ABSTRACTThe structures and electronic properties of graphene with defects consisting of one to six atomic vacancies are investigated using first-principles calculation. All of the geometrically possible initial structures of a movacancy or a multivacancy in graphene are equilibrated. The formation energies and electronic band structures for the equilibrated defective structures are calculated. It is suggested non-zero bandgaps may be induced in graphene by introducing some types of monovacancy or multivacancy although further checks regarding supercell size are necessary to ensure the present results.

Electronic Properties of Hydrogenated Graphene-Like Materials Under Strains

2014 ◽  
Vol 1658 ◽  
Author(s):  
K. Mihara ◽  
K. Shintani
Keyword(s):  
Band Gap ◽  
First Principles ◽  
Tensile Strain ◽  
Band Gaps ◽  
First Principles Calculation ◽  
Honeycomb Lattice ◽  
Electronic Band ◽  
Hydrogenated Graphene ◽  
Zigzag Direction ◽  
Electronic Band Structures

ABSTRACTThe electronic band structures of the hydrogenated graphene-like materials, graphane, silicane, and germanane, under tensile strains are calculated using first-principles calculation. The imposed tensile strain is in either the armchair or zigzag direction in the honeycomb lattice. It is found that the band gap of graphane gradually increases with the increase of the strain, whereas the band gaps of silicane and germanane decrease with the increase of the strain. There is little effect of the direction of the imposed strain on such strain dependences.

Electronic properties of monolayer molybdenum dichalcogenides under strains

2015 ◽  
Vol 1726 ◽  
Author(s):  
J. Sugimoto ◽  
K. Shintani
Keyword(s):  
First Principles ◽  
Tensile Strain ◽  
Compressive Strain ◽  
Band Gaps ◽  
First Principles Calculation ◽  
Honeycomb Lattice ◽  
Biaxial Strain ◽  
Electronic Band ◽  
Zigzag Direction ◽  
Electronic Band Structures

ABSTRACTThe electronic band structures of monolayer molybdenum dichalcogenides, MoS2, MoSe2, and MoTe2 under either uniaxial or biaxial strain are calculated using first-principles calculation with the GW method. The imposed uniaxial strain is in the zigzag direction in the honeycomb lattice whereas the imposed biaxial strain is in the zigzag and armchair directions. It is found that the band gaps of these dichalcogenides almost linearly increase with the decrease of the magnitude of compressive strain, reach their maxima at some compressive strain, and then decrease almost linearly with the increase of tensile strain. It is also found their maximum band gaps are direct bandgaps.

First-principles investigation of the electronic band structures and optical properties of quaternary ABaMQ4 (A = Rb, Cs; M = P, V; and Q = S) metal chalcogenides

2018 ◽  
Vol 32 (30) ◽  
pp. 1850337
Author(s):  
Shahid Ullah ◽  
Hayat Ullah ◽  
Abdullah Yar ◽  
Sikander Azam ◽  
A. Laref
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Correlation Energy ◽  
Electronic Charge ◽  
Electromagnetic Spectrum ◽  
Metal Chalcogenides ◽  
Electronic Band ◽  
Charge Densities ◽  
Electronic Band Structures

In this paper, we study the optoelectronic properties of quaternary metal chalcogenide semiconductor ABaMQ4 (A = Rb, Cs; M = P, V; and Q = S) compounds using state-of-the-art density functional theory (DFT) with TB-mBJ approximation for the treatment of exchange-correlation energy. In particular, the electronic and optical properties of the relaxed geometries of these compounds are investigated. Our first-principles ab-initio calculations show that the CsBaPS4 and RbBaPS4 compounds have direct bandgaps whereas the CsBaVS4 compound exhibits indirect bandgap nature. Importantly, the theoretically calculated values of the bandgaps of the compounds are consistent with experiment. Furthermore, our analysis of the electronic charge densities of these compounds indicates that the above quaternary chalcogenides have mixed covalent and ionic bonding characters. The effective masses of these compounds are also calculated which provide very useful information about the band structure and transport characteristics of the investigated compounds. Similarly, high absorptivity in the visible and ultraviolet regions of the electromagnetic spectrum possibly predicts and indicates the importance of these materials for potential optoelectronic applications in this range.

First Principles Study of Elastic Properties, Mechanical Properties and Electronic Band Structures of LiGaO2 Phases

2021 ◽  
Vol 223 (1) ◽  
pp. 68-80
Author(s):  
Thanit Saisopa ◽  
Chakrit Nualchimplee ◽  
Yuttakarn Rattanachai ◽  
Kompichit Seehamart ◽  
Isara Kotutha ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Properties ◽  
First Principles ◽  
Band Structures ◽  
Electronic Band ◽  
First Principles Study ◽  
Electronic Band Structures

Half-metallic properties in Co2XSn (X = Ti, V and Cr) full-Heusler compound

2019 ◽  
Vol 34 (02) ◽  
pp. 2050028 ◽  
Author(s):  
H. Abbassa ◽  
A. Labdelli ◽  
S. Meskine ◽  
Y. Benaissa Cherif ◽  
A. Boukortt
Keyword(s):  
Magnetic Moment ◽  
Density Functional ◽  
Heusler Alloys ◽  
Electronic Band ◽  
Half Metallic ◽  
Lattice Constants ◽  
Half Metal ◽  
Wide Range ◽  
Metallic Ferromagnetism ◽  
Half Metallic Ferromagnetism

First-principles calculations based on density functional theory (DFT) confirm the half-metallic ferromagnetism in both [Formula: see text] and [Formula: see text], and the nearly half-metallic ferromagnetism in [Formula: see text] Heusler alloys with the [Formula: see text]-type structure [Formula: see text]. The electronic band structures and density of states (DOS) calculations of the [Formula: see text] and [Formula: see text] compounds show that the spin-up electrons are metallic, whereas the spin-down bands are semiconducting with a gap of 0.47 eV and 0.53 eV, respectively, with 0.21 eV and 0.36 eV as a spin-flip gap, respectively. The [Formula: see text] and [Formula: see text] Heusler were half-metal compounds with magnetic moment of [Formula: see text] and [Formula: see text] at the equilibrium lattice constants [Formula: see text] Å and [Formula: see text] Å, respectively, which agrees with the Slater–Pauling rule, and have 100% polarization for a wide range of lattice parameters. The [Formula: see text] is a nearly half-metal (NHF) compound with magnetic moment of [Formula: see text] and 92.9% polarization at the equilibrium lattice constants [Formula: see text] Å and acquire half-metal behavior under the pressure 16.70 GPa.

First-Principles Study of the New Half-Metallic Ferromagnetic Quaternary-Heusler Alloys NaXNO (X=Ca, Sr, Ba)

SPIN ◽  
2020 ◽  
Vol 10 (03) ◽  
pp. 2050022 ◽  
Author(s):  
K. Belkacem ◽  
Y. Zaoui ◽  
S. Amari ◽  
L. Beldi ◽  
B. Bouhafs
Keyword(s):  
Magnetic Properties ◽  
Density Of States ◽  
First Principles ◽  
Density Functional ◽  
Heusler Alloys ◽  
Exchange Potential ◽  
Energy Calculation ◽  
Full Potential ◽  
Electronic Band ◽  
Half Metallic

The first-principles approach based on density functional theory (DFT) and the full-potential linearized augmented plane-wave method were employed to investigate the structural, elastic, electronic and magnetic properties of Na[Formula: see text]NO ([Formula: see text], Sr and Ba) quaternary half-Heusler alloys. The generalized gradient approximation (GGA) as parameterized by Perdew, Burke and Ernzerhof (PBE) and the modified Becke–Johnson exchange potential were used. As far as we know, we present our results which for the first time quantitatively account for the electronic structures and magnetic properties of Na[Formula: see text]NO ([Formula: see text], Sr and Ba) quaternary half-Heusler alloys. From the total energy calculation using three possible atomic configurations ([Formula: see text], [Formula: see text] and [Formula: see text]), it is found that the Na[Formula: see text]NO ([Formula: see text], Sr and Ba) quaternary half-Heusler alloys are more stable in the ferromagnetic [Formula: see text]-phase. From our estimated elastic constants [Formula: see text], it is found that all the considered Heusler alloys are mechanically stable in the [Formula: see text]-phase. We have also investigated the robustness of the half-metallicity with respect to the variation of lattice constants in these alloys. We have found that these alloys are half-metallic ferromagnets (HMFs) with a magnetic moment of 2[Formula: see text][Formula: see text] per formula unit at their equilibrium volumes. The spin-polarized electronic band structure and density of states of these quaternary half-Heusler alloys calculated by GGA (mBJ-GGA) show that the minority spin channels have metallic nature and the majority spin channels have a semiconductor character with half-metallic gaps of 0.49[Formula: see text]eV (2.17[Formula: see text]eV), 0.72[Formula: see text]eV (2.28[Formula: see text]eV) and 0.96[Formula: see text]eV (2.22[Formula: see text]eV) for NaCaNO, NaSrNO and NaBaNO quaternary half-Heusler alloys, respectively. Analysis of the density of states and the spin charge density of these quaternary alloys indicates that their magnetic moments mainly originate from the strong spin-polarization of 2[Formula: see text] states of N atoms and O atoms.

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