The role of stoichiometry in superconducting Nb1−βSnβ: electronic and vibrational properties from ab initio calculations

2016 ◽  
Vol 18 (48) ◽  
pp. 32840-32846 ◽  
Author(s):  
F. Gala ◽  
G. De Marzi ◽  
L. Muzzi ◽  
G. Zollo
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
First Principles ◽  
Vibrational Properties ◽  
First Principles Calculations ◽  
Superconducting Properties ◽  
A15 Phase ◽  
Stoichiometry Ratios

Using first principles calculations the electronic, vibrational and superconducting properties of Nb3Sn compounds with different stoichiometry ratios in the A15 phase have been studied.

Solubility Products for Precipitate Phases in Steels from First-principles Calculations

2011 ◽  
Vol 1296 ◽  
Author(s):  
Tetyana Klymko ◽  
Chaitanya Krishna Ande ◽  
Marcel Sluiter
Keyword(s):  
Ab Initio ◽  
First Principles ◽  
First Principles Calculations ◽  
Experimental Phase Diagram ◽  
Formation Enthalpies ◽  
Enthalpy And Entropy ◽  
Solubility Products ◽  
Diagram Analysis ◽  
Insight Into

ABSTRACTThe work presented gives an insight into using formation enthalpies determined from ab initio calculations for computing solubility products in steels. The role of enthalpy and entropy contributions to the solubility product is discussed. As an illustration of the method, we present solubility products for observed stoichiometric precipitate phases in ferrite from first-principles calculations and in austenite as obtained from the combined approach based on ab initio and experimental phase diagram analysis. The results are compared with experimental data where available.

Electronic and magnetic properties of BN nanosheet superlattices: First-principles calculations

2018 ◽  
Vol 32 (31) ◽  
pp. 1850348
Author(s):  
Xiao-Qin Feng ◽  
Hong-Xia Lu ◽  
Jian-Ming Jia ◽  
Chang-Shun Wang
Keyword(s):  
Magnetic Properties ◽  
Boron Nitride ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Electronic Properties ◽  
First Principles ◽  
First Principles Calculations ◽  
Electronic And Magnetic Properties ◽  
Boron Nitride Nanosheet

Systematic ab initio calculations reveal that the electronic and magnetic properties are modified by superlattices of zigzag and armchair Boron nitride nanosheet (BNNS). Superlattices are constructed by partially hydrogenated B and N atoms of BNNS. The results show that only no more than half N atoms hydrogenated superlattices are antiferromagnetic. The electronic properties of zigzag BN nanosheet superlattices depend on the degree of hydrogenation of N atoms sensitively. As a result, changing the degree of hydrogenation of N atoms results in the transition from semiconductor to metal.

scholarly journals Origin of the Dzyaloshinskii-Moriya Interactions in the Intermetallic RMn2Si2 ( R= La, Ce, Yb and Y) Materials: A DFT Study

2021 ◽  
Author(s):  
Widad Bazine ◽  
Najim TAHIRI ◽  
Omar Elbounagui ◽  
Hamid Ez-Zahraouy
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Density Of States ◽  
First Principles ◽  
Giant Magnetoresistance ◽  
Dft Study ◽  
Spin Orbit ◽  
First Principles Calculations ◽  
Strong Hybridization ◽  
Large Spin

Abstract The Dzyaloshinskii-Moriya interactions (DM) are investigated using first-principles calculations by means of the WIENNCM code, an implementation of the FP-LAPW method. The intermetallic RMn2Si2 (R = La, Ce, Yb, and Y) materials exhibit a large spin-orbit effect after the density of states; they found a strong hybridization between Mn-Si and Mn-R atoms. Also, show a large noncollinear magnetic configuration depending on the R atoms. By using ab-initio calculations, the RKKY effect is observed in the RMn2Si2 materials, which shows explicitly the existence of the giant magnetoresistance (GMR) in these materials. Explicitly, the mechanisms responsible for the magnetoelectric coupling are due to relatively the effect of the presence of the Dzyaloshinskii-Moriya term.

A Comparative Study of GaAsO4 Polymorphs: ab initio Calculations on High-pressure Forms

2008 ◽  
Vol 63 (6) ◽  
pp. 668-672 ◽  
Author(s):  
Elena Arroyo y de Dompablo ◽  
Emilio Morán
Keyword(s):  
High Pressure ◽  
Comparative Study ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
First Principles ◽  
Relative Stability ◽  
First Principles Calculations ◽  
Pressure Behavior ◽  
Hexagonal Form ◽  
Pressure Phase

First-principles calculations were performed to compare the relative stability and high-pressure behavior of four different GaAsO4 polymorphs: the ordinary-pressure phase (berlinite, α-quartzlike) and three high-pressure phases: the β -VCrO4-like, the rutile-like and a new hexagonal form, recently discovered and related to rutile.

An effective and efficient approach to p-type AlN by Be2:O codoping from first-principles calculations

2016 ◽  
Vol 30 (20) ◽  
pp. 1650257
Author(s):  
Meng Zhao ◽  
Wenjun Wang ◽  
Jun Wang ◽  
Junwei Yang ◽  
Weijie Hu ◽  
...  
Keyword(s):  
First Principles ◽  
Ionization Energy ◽  
Hole Concentration ◽  
Valence Band Maximum ◽  
First Principles Calculations ◽  
Mutual Compensation ◽  
Efficient Approach ◽  
P Type ◽  
Codoping Method

Various Be:O-codoped AlN crystals have been investigated via first-principles calculations to evaluate the role of the different combinations in effectively and efficiently inducing p-type carriers. It is found that the O atom is favored to bond with two Be atoms. The formed Be2:O complexes decrease the acceptor ionization energy to 0.11 eV, which is 0.16 eV lower than that of an isolated Be in AlN, implying that the hole concentration could probably be increased by 2–3 orders of magnitude. The electronic structure of Be2:O-codoped AlN shows that the lower ionization energy can be attributed to the interaction between Be and O. The Be–O complexes, despite failing to induce p-type carriers for the mutual compensation of Be and O, introduce new occupied states on the valence-band maximum (VBM) and hence the energy needed for the transition of electrons to the acceptor level is reduced. Thus, the Be2:O codoping method is expected to be an effective and efficient approach to realizing p-type AlN.

Computational and Experimental Insights into the Role of Acidic Molecules on the Corrosion Behavior on 7A46 Aluminum Alloy

2021 ◽  
Vol 21 (4) ◽  
pp. 2221-2233
Author(s):  
Yaru Liu ◽  
Qinglin Pan ◽  
Xiangdong Wang ◽  
Ye Ji ◽  
Qicheng Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
First Principles ◽  
First Principles Calculations ◽  
Corrosive Media ◽  
Corrosion Depth ◽  
Corrosion Mechanisms ◽  
Nanoscale Level

The corrosion mechanisms for different corrosive media on the aged 7A46 aluminum alloy were systematically investigated at nanoscale level. The combination of empirical intergranular and exfoliation corrosion behavior was employed, and coupled with first-principles calculations. Results revealed that the dispersed distribution of matrix precipitates (MPs) leads to the enhancement of the corrosion resistance pre-ageing (PA) followed by double-ageing (PA-DA) alloy. The deepest corrosion depth of PA-DA alloy was in hydrochloric acid, and the calculation result demonstrates that the passivation effect in combination with the accumulation of corrosion products in nitric acid protect the PA-DA alloy from further corrosion.

scholarly journals Three-nucleon forces

2014 ◽  
Vol 23 (09) ◽  
pp. 1430015 ◽  
Author(s):  
Peter U. Sauer
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Body Problem ◽  
Many Body ◽  
Nuclear Systems ◽  
The Difference

In this paper, the role of three-nucleon forces in ab initio calculations of nuclear systems is investigated. The difference between genuine and induced many-nucleon forces is emphasized. Induced forces arise in the process of solving the nuclear many-body problem as technical intermediaries toward calculationally converged results. Genuine forces make up the Hamiltonian. They represent the chosen underlying dynamics. The hierarchy of contributions arising from genuine two-, three- and many-nucleon forces is discussed. Signals for the need of the inclusion of genuine three-nucleon forces are studied in nuclear systems, technically best under control, especially in three-nucleon and four-nucleon systems. Genuine three-nucleon forces are important for details in the description of some observables. Their contributions to observables are small on the scale set by two-nucleon forces.

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