Magnetic properties of Fe-pnictides superconductors as a function of pressure and doping

2012 ◽  
Vol 1434 ◽  
Author(s):  
Gianni Profeta ◽  
Nicola Colonna ◽  
Alessandra Continenza
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
First Principles ◽  
Local Magnetic Moment ◽  
Theoretical Description ◽  
Pressure Effects ◽  
Experimental Conditions ◽  
Long Wavelength ◽  
Local Fluctuations ◽  
Pressure Phase

ABSTRACTWe present a first principles study of the electronic and magnetic properties of Fe-based pnicitdes superconductors as a function of pressure and doping. We show that the magnetic phase and a local magnetic moment persists at doping level quite larger than what found in experiments and the pressure phase diagram consists of a paramagnetic, antiferromagnetic and non-magnetic phases.Although this result calls for the inclusion of long-wavelength or local fluctuations of iron magnetic moment and non-hydrostatic pressure effects, in order to improve the theoretical description of real experimental conditions, recent photoemission experiments[1] reconcile these DFT results, showing a local magnetic moment on Fe site different from zero in the paramagnetic, antiferromagnetic and the superconducting phase.

scholarly journals Stability and local magnetic moment of bilayer graphene by intercalation: first principles study

RSC Advances ◽  
2018 ◽  
Vol 8 (35) ◽  
pp. 19732-19738 ◽  
Author(s):  
Jinsen Han ◽  
Dongdong Kang ◽  
Jiayu Dai
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
First Principles ◽  
Local Magnetic Moment ◽  
Bilayer Graphene ◽  
Intercalation Compounds ◽  
First Principles Study ◽  
Magnetic Elements

The migration and magnetic properties of the bilayer graphene with intercalation compounds (BGICs) with magnetic elements are theoretically investigated based on first principles study.

Tunable electronic structure and magnetic moment in C2N nanoribbons with different edge functionalization atoms

2017 ◽  
Vol 19 (23) ◽  
pp. 15021-15029 ◽  
Author(s):  
Yusheng Wang ◽  
Nahong Song ◽  
Min Jia ◽  
Dapeng Yang ◽  
Chikowore Panashe ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Electronic Structure ◽  
Magnetic Moment ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Electronic And Magnetic Properties

First principles calculations based on density functional theory were carried out to study the electronic and magnetic properties of C2N nanoribbons (C2NNRs).

Width-dependent structural stability and magnetic properties of monolayer zigzag MoS2 nanoribbons

2017 ◽  
Vol 31 (03) ◽  
pp. 1750017 ◽  
Author(s):  
Yan-Ni Wen ◽  
Peng-Fei Gao ◽  
Xi Chen ◽  
Ming-Gang Xia ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Structural Stability ◽  
Magnetic Moment ◽  
First Principles ◽  
Density Functional ◽  
Electronic States ◽  
Two Dimensional ◽  
Functional Theory ◽  
Proportional Relationship

First-principles study based on density functional theory has been employed to investigate width-dependent structural stability and magnetic properties of monolayer zigzag MoS2 nanoribbons (ZZ-MoS2 NRs). The width N = 4–6 (the numbers of zigzag Mo–S chains along the ribbon length) are considered. The results show that all studied ZZ-MoS2 NRs are less stable than two-dimensional MoS2 monolayer, exhibiting that a broader width ribbon behaves better structural stability and an inversely proportional relationship between the structural stability (or the ribbon with) and boundary S–Mo interaction. Electronic states imply that all ZZ-MoS2 NRs exhibit magnetic properties, regardless of their widths. Total magnetic moment increases with the increasing width N, which is mainly ascribed to the decreasing S–Mo interaction of the two zigzag edges. In order to confirm this reason, a uniaxial tension strain is applied to ZZ-MoS2 NRs. It has been found that, with the increasing tension strain, the bond length of boundary S–Mo increases, at the same time, the magnetic moment increases also. Our results suggest the rational applications of ZZ-MoS2 NRs in nanoelectronics and spintronics.

Structural and Magnetic Study on the Effect of Substitution of Cobalt by d-Valent Elements of Co2FeSi Heusler Alloy

2016 ◽  
Vol 708 ◽  
pp. 37-41
Author(s):  
Muhammad Noor Syazwan Saimin ◽  
Siti Sumaiyah Sheikh Abdul Aziz ◽  
A.M.M. Ali ◽  
Oskar Hasdinor Hassan ◽  
Muhd Zu Azhan Yahya ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
Band Structure ◽  
Fermi Level ◽  
Density Of States ◽  
Magnetic Moment ◽  
Local Magnetic Moment ◽  
Half Metallic ◽  
New States ◽  
Full Heusler

In this paper, the effect of substitution of Co by d-valent elements such as Ag and Pt on electronic structure and magnetic properties of full Heusler type Co2FeSi alloys was investigated. Structural study reveals the presence of a small gap in the minority band structure around the vicinity of the Fermi level on Co2FeSi resulting to half-metallic behaviour. However, CoFeSiAg and CoFeSiPt cannot preserved the half-metalicity due to disappearing of the gap in the minority band structure due to the creation of new states around the Fermi level in the minority density of states. The variation in the magnetic moment of Co2FeSi with change of the atoms was attributed to the change in the local magnetic moment of atoms.

Martensitic transformation and magnetic properties in Pd2MnGa Heusler alloy by DFT study

2019 ◽  
Vol 33 (07) ◽  
pp. 1950074
Author(s):  
Bin Yang ◽  
Zhinan Li ◽  
Fanghui Zhu ◽  
Liwu Jiang ◽  
Chuan-Hui Zhang
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
Martensitic Transformation ◽  
Magnetic Moment ◽  
First Principles ◽  
Heusler Alloy ◽  
Theoretical Calculations ◽  
Text Structure ◽  
Dft Study ◽  
First Principles Calculations

The electronic structure, martensitic transformation and magnetic properties of [Formula: see text] Heusler alloy were studied by first-principles calculations. It is found that the stable structure of austenitic [Formula: see text] is the ferromagnetic [Formula: see text] structure, and a martensitic transformation is possible to occur with the distortion degree of 1.26. By the analysis of the electronic structure, some results of magnetic moment are consistent with previous theoretical calculations.

Structural, electronic and magnetic properties of S sites vacancy defects graphene/MoS2 van der Waals heterostructures: First-principles study

2021 ◽  
pp. 2150009
Author(s):  
Hari Krishna Neupane ◽  
Narayan Prasad Adhikari
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
First Principles ◽  
Density Functional ◽  
Dominant Role ◽  
Van Der Waals ◽  
Schottky Contact ◽  
Unequal Distribution ◽  
Vacancy Defects ◽  
Electronic And Magnetic Properties

In this work, we investigated the geometrical structures, electronic and magnetic properties of S sites vacancy defects in heterostructure graphene/molybdenum disulphide ((HS)G/MoS[Formula: see text] material by performing first-principles calculations based on spin polarized Density Functional Theory (DFT) method within van der Waals (vdW) corrections (DFT-D2) approach. All the structures are optimized and relaxed by BFGS method using computational tool Quantum ESPRESSO (QE) package. We found that both (HS)G/MoS2 and S sites vacancy defects in (HS)G/MoS2 (D1S–(HS)G/MoS2, U1S–(HS)G/MoS2, 2S–(HS)G/MoS2 and 3S–(HS)G/MoS[Formula: see text] are stable materials, and atoms in defects structures are more compact than in pristine (HS)G/MoS2 structure. From band structure calculations, we found that (HS)G/MoS2, (D1S–(HS)G/MoS2, U1S–(HS)G/MoS2, 2S–(HS)G/MoS2 and 3S–(HS)G/MoS[Formula: see text] materials have [Formula: see text]-type Schottky contact. The Dirac cone is formed in conduction band of the materials mentioned above. The barrier height of Dirac cones from Fermi energy level of (HS)G/MoS2, (D1S–(HS)G/MoS2, U1S–(HS)G/MoS2, 2S–(HS)G/MoS2 and 3S–(HS)G/MoS[Formula: see text] materials have values 0.56[Formula: see text]eV, 0.62[Formula: see text]eV, 0.62[Formula: see text]eV, 0.64[Formula: see text]eV and 0.65[Formula: see text]eV, respectively, which means they have metallic properties. To study the magnetic properties of materials, we have carried out DoS and PDoS calculations. We found that (HS)G/MoS2, D1S–(HS)G/MoS2 and U1S–(HS)G/MoS2 materials have non-magnetic properties, and 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials have magnetic properties. Therefore, the non-magnetic (HS)G/MoS2 changes to magnetic 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials due to 2S and 3S atoms vacancy defects, respectively, in (HS)G/MoS2 material. Magnetic moment obtained in 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials due to the unequal distribution of up and down spin states of electrons in 2s and 2p orbitals of C atoms; 4p, 4d and 5s orbitals of Mo atoms; and 3s and 3p orbitals of S atoms in structures. Magnetic moment of 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials is −0.11[Formula: see text][Formula: see text]/cell and [Formula: see text]/cell, respectively, and spins of 2p orbital of C atoms, 3p orbital of S atoms and 4d orbital of Mo atoms have dominant role to create magnetism in 2S–(HS)G/MoS2 and 3S–(HS)G/MoS2 materials.

A New Heusler Alloy of V2NiGa: A First-Principles Study

2013 ◽  
Vol 710 ◽  
pp. 174-177
Author(s):  
Lei Feng ◽  
Fei Wang ◽  
Ju Gao ◽  
Jin Zhi Yin ◽  
Xiu Yan Luo
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
First Principles ◽  
Heusler Alloy ◽  
Magnetic Moments ◽  
Unit Cell ◽  
Total Magnetic Moment ◽  
Type Structure ◽  
First Principles Calculations ◽  
Band Structures

A new Heusler alloyV2NiGawith Hg2CuTi-type structure was investigated by first-principles calculations. The band structures and magnetic properties have been studied. The alloy has a total magnetic moment of 1.05μBper unit cell on first-principles calculations which is in agreement with theSlaterPauling(SP) rule. The magnetic moments ofV(1) atom andV(2) atom are 1.28μBand-0.44μBrespectively, so the alloy is a ferrimagnetism.

Mn Adsorption on the GaAs(111)–(2×2)B Surface: First Principles Studies

2016 ◽  
Vol 230 (5-7) ◽  
Author(s):  
Jonathan Guerrero-Sanchez ◽  
J. Castro-Medina ◽  
J. F. Rivas-Silva ◽  
Noboru Takeuchi ◽  
L. Morales de la Garza ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Magnetic Moment ◽  
First Principles ◽  
Density Functional ◽  
Interstitial Atom ◽  
Ferromagnetic Behavior ◽  
Functional Theory ◽  
Spin Polarized ◽  
A Chain

AbstractMn adsorption on the GaAs(111)–(1×1)B surface electronic and magnetic properties are investigated using first principles total energy calculations within the periodic spin polarized density functional theory. Results show that one Mn atom adsorption on top of the surface drives to an interstitial Mn atom. The interstitial atom is bonded to three first monolayer As atoms forming a chain-like structure. This stable structure has a ferromagnetic behavior with a Mn magnetic moment of ∼ 3.98 μ

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