scholarly journals The effects of refractory elements on Ni-excesses and Ni-depletions at γ(f.c.c.)/γ′(L12) interfaces in model Ni-based superalloys: Atom-probe tomographic experiments and first-principles calculations

2016 ◽  
Vol 121 ◽  
pp. 288-298 ◽  
Author(s):  
Yanyan Huang ◽  
Zugang Mao ◽  
Ronald D. Noebe ◽  
David N. Seidman
Keyword(s):  
First Principles ◽  
Atom Probe ◽  
First Principles Calculations ◽  
Refractory Elements

Mapping energetics of atom probe evaporation events through first principles calculations

2013 ◽  
Vol 132 ◽  
pp. 143-151 ◽  
Author(s):  
Joaquín Peralta ◽  
Scott R. Broderick ◽  
Krishna Rajan
Keyword(s):  
First Principles ◽  
Atom Probe ◽  
First Principles Calculations

scholarly journals Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hisao Nakamura ◽  
Johannes Hofmann ◽  
Nobuki Inoue ◽  
Sebastian Koelling ◽  
Paul M. Koenraad ◽  
...  
Keyword(s):  
Topological Insulator ◽  
First Principles ◽  
Atom Probe ◽  
Photoemission Spectroscopy ◽  
Band Offset ◽  
First Principles Calculations ◽  
Vacuum Interface ◽  
Topological States ◽  
Experimental Findings ◽  
Thick Layers

AbstractThe interface between topological and normal insulators hosts metallic states that appear due to the change in band topology. While topological states at a surface, i.e., a topological insulator-air/vacuum interface, have been studied intensely, topological states at a solid-solid interface have been less explored. Here we combine experiment and theory to study such embedded topological states (ETSs) in heterostructures of GeTe (normal insulator) and $$\hbox {Sb}_2$$ Sb 2 $$\hbox {Te}_3$$ Te 3 (topological insulator). We analyse their dependence on the interface and their confinement characteristics. First, to characterise the heterostructures, we evaluate the GeTe-Sb$$_2$$ 2 Te$$_3$$ 3 band offset using X-ray photoemission spectroscopy, and chart the elemental composition using atom probe tomography. We then use first-principles to independently calculate the band offset and also parametrise the band structure within a four-band continuum model. Our analysis reveals, strikingly, that under realistic conditions, the interfacial topological modes are delocalised over many lattice spacings. In addition, the first-principles calculations indicate that the ETSs are relatively robust to disorder and this may have practical ramifications. Our study provides insights into how to manipulate topological modes in heterostructures and also provides a basis for recent experimental findings [Nguyen et al. Sci. Rep. 6, 27716 (2016)] where ETSs were seen to couple over thick layers.

Composition of β″ precipitates in Al–Mg–Si alloys by atom probe tomography and first principles calculations

2009 ◽  
Vol 106 (12) ◽  
pp. 123527 ◽  
Author(s):  
Håkon S. Hasting ◽  
Anders G. Frøseth ◽  
Sigmund J. Andersen ◽  
Rene Vissers ◽  
John C. Walmsley ◽  
...  
Keyword(s):  
First Principles ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
First Principles Calculations

scholarly journals Elemental Phase Partitioning in the γ-γ″ Ni2CoFeCrNb0.15 High Entropy Alloy

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 910 ◽  
Author(s):  
Bin Han ◽  
Jie Wei ◽  
Feng He ◽  
Da Chen ◽  
Zhi Wang ◽  
...  
Keyword(s):  
First Principles ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
Alloying Elements ◽  
High Entropy Alloy ◽  
First Principles Calculations ◽  
Specific Chemical ◽  
High Entropy ◽  
Phase Partitioning ◽  
Chemical Potentials

The partitioning of the alloying elements into the γ″ nanoparticles in a Ni2CoFeCrNb0.15 high entropy alloy was studied by the combination of atom probe tomography and first-principles calculations. The atom probe tomography results show that the Co, Fe, and Cr atoms incorporated into the Ni3Nb-type γ″ nanoparticles but their partitioning behaviors are significantly different. The Co element is much easier to partition into the γ″ nanoparticles than Fe and Cr elements. The first-principles calculations demonstrated that the different partitioning behaviors of Co, Fe and Cr elements into the γ″ nanoparticles resulted from the differences of their specific chemical potentials and bonding states in the γ″ phase.

Electronic Structure and X-ray Absorption Spectra of Rutile TiO2 Using First-Principles Calculations

2014 ◽  
Vol 52 (12) ◽  
pp. 1025-1029
Author(s):  
Min-Wook Oh ◽  
Tae-Gu Kang ◽  
Byungki Ryu ◽  
Ji Eun Lee ◽  
Sung-Jae Joo ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Absorption Spectra ◽  
First Principles ◽  
First Principles Calculations ◽  
Rutile Tio2 ◽  
X Ray ◽  
X Ray Absorption

To Bend or Not to Bend, the Dilemma of Multiple Bonds

2019 ◽  
Author(s):  
Michele Pizzocchero ◽  
Matteo Bonfanti ◽  
Rocco Martinazzo
Keyword(s):  
First Principles ◽  
2D Materials ◽  
Main Group ◽  
First Principles Calculations ◽  
Group 14 ◽  
Multiple Bonds ◽  
Main Group Elements ◽  
Structural Distortions

The manuscript addresses the issue of the structural distortions occurring at multiple bonds between high main group elements, focusing on group 14. These distortions are known as trans-bending in silenes, disilenes and higher group analogues, and buckling in 2D materials likes silicene and germanene. A simple but correlated \sigma + \pi model is developed and validated with first-principles calculations, and used to explain the different behaviour of second- and higher- row elements.

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