scholarly journals First principles DFT study of interstitial hydrogen and oxygen atoms in the MAX phase Ti2AlN

RSC Advances ◽  
2017 ◽  
Vol 7 (60) ◽  
pp. 37852-37857 ◽  
Author(s):  
Francesco Colonna ◽  
Christian Elsässer
Keyword(s):  
Ab Initio ◽  
Corrosion Protection ◽  
First Principles ◽  
Dft Study ◽  
Max Phase ◽  
Oxygen Absorption ◽  
Protection Potential ◽  
And Diffusion ◽  
Interstitial Hydrogen ◽  
Oxygen Atoms

We model hydrogen and oxygen absorption and diffusion in Ti2AlN via ab initio simulations to assess its corrosion protection potential.

scholarly journals Ionicity and birefringence of α-LiNH4SO4crystals: ab initio DFT study, X-ray spectroscopy measurements

RSC Advances ◽  
2017 ◽  
Vol 7 (12) ◽  
pp. 6889-6901 ◽  
Author(s):  
M. Ya. Rudysh ◽  
M. G. Brik ◽  
O. Y. Khyzhun ◽  
A. O. Fedorchuk ◽  
I. V. Kityk ◽  
...  
Keyword(s):  
Band Structure ◽  
Ab Initio ◽  
Electronic Properties ◽  
First Principles ◽  
Experimental Studies ◽  
Dft Study ◽  
X Ray ◽  
Complex Approach ◽  
Ab Initio Dft

The structural, electronic properties and ionicity of the α-LiNH4SO4dielectric crystals are examined using a complex approach: experimental studies of X-ray spectroscopy and the first principles band structure techniques within a framework of DFT.

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.

Ab initio Study of Metal Atoms on SWNT Surface

2001 ◽  
Vol 675 ◽  
Author(s):  
Shu Peng ◽  
Kyeongjae Cho
Keyword(s):  
Carbon Nanotube ◽  
Binding Energy ◽  
Ab Initio ◽  
Diffusion Barrier ◽  
First Principles ◽  
Ab Initio Study ◽  
Single Walled Carbon Nanotube ◽  
Metal Atoms ◽  
Pseudopotential Calculations ◽  
And Diffusion

ABSTRACTInteractions of metal atoms (Al, Ti) with semiconducting single walled carbon nanotube (SWNT) are investigated using first-principles pseudopotential calculations. Six different adsorption configurations for aluminum and titanium atoms are studied. Comparison of the energetics of these metal atoms on (8,0) SWNT surface shows significant differences in binding energy and diffusion barrier. These differences give an insight to explain why most of metal atoms (such as Al) form discrete particles on nanotube while continuous nanowires are obtained by using titanium in the experiment.

Ru Passivated and Ru Doped e-TaN surfaces as Combined Barrier and Liner Material for Copper Interconnects: A First Principles Study

2018 ◽  
Author(s):  
Suresh Natarajan ◽  
Cara-Lena Nies ◽  
Michael Nolan
Keyword(s):  
First Principles ◽  
Film Growth ◽  
Early Stage ◽  
Copper Interconnects ◽  
Liner Material ◽  
Critical Dimensions ◽  
Industry Standard ◽  
Cu Film ◽  
Improved Performance ◽  
And Diffusion

<div>As the critical dimensions of transistors continue to be scaled down to facilitate improved performance and device speeds, new ultrathin materials that combine diffusion barrier and seed/liner properties are needed for copper interconnects at these length scales. Ideally, to facilitate coating of high aspect ratio structures, this alternative barrier+liner material should only consist of one or as few layers as possible. We studied TaN, the current industry standard for Cu diffusion barriers, and Ru, which is a</div><div>suitable liner material for Cu electroplating, to explore how combining these two materials in a barrier+liner material influences the adsorption of Cu atoms in the early stage of Cu film growth. To this end, we carried out first-principles simulations of the adsorption and diffusion of Cu adatoms at Ru-passivated and Ru-doped e-TaN(1 1 0) surfaces. For comparison, we also studied the behaviour of Cu and Ru adatoms at the low index surfaces of e-TaN, as well as the interaction of Cu adatoms with the (0 0 1) surface of hexagonal Ru. Our results confirm the barrier and liner properties of TaN and Ru, respectively while also highlighting the weaknesses of both materials. Ru passivated TaN was found to have improved binding with Cu adatoms as compared to the bare TaN and Ru surfaces.</div><div>On the other hand, the energetic barrier for Cu diffusion at Ru passivated TaN surface was lower than at the bare TaN surface which can promote Cu agglomeration. For Ru-doped TaN however, a decrease in Cu binding energy was found in addition to favourable migration of the Cu adatoms toward the doped Ru atom and unfavourable migration away from it or into the bulk. This suggests that Ru doping sites in the TaN surface can act as nucleation points for Cu growth with high migration barrier preventing agglomeration and allow electroplating of Cu. Therefore Ru-doped TaN is proposed as a candidate for a combined barrier+liner material with reduced thickness.</div>

Flexoelectricity in atomic monolayers from first principles

Nanoscale ◽  
2020 ◽  
Author(s):  
Shashikant Kumar ◽  
David Codony ◽  
Irene Arias ◽  
Phanish Suryanarayana
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Ab Initio ◽  
First Principles ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Functional Theory ◽  
Group Iii ◽  
Flexoelectric Effect ◽  
Metal Dichalcogenides

We study the flexoelectric effect in fifty-four select atomic monolayers using ab initio Density Functional Theory (DFT). Specifically, considering representative materials from each of Group III monochalcogenides, transition metal dichalcogenides...

Li Uptake in Carbon Nanotube Systems: A First Principles Investigation

2001 ◽  
Vol 706 ◽  
Author(s):  
Vincent Meunier ◽  
Jeremy Kephart ◽  
Christopher Roland ◽  
Jerry Bernholc
Keyword(s):  
Carbon Nanotube ◽  
Ab Initio ◽  
Ball Milling ◽  
First Principles ◽  
Topological Defects ◽  
Ion Bombardment ◽  
Ion Uptake ◽  
Li Ion ◽  
Pass Through ◽  
Non Equilibrium

AbstractCarbon nanotube systems can substantially increase their capacity for Li ion uptake, provided that the nanotube interiors become accessible to the ions. We examine theoretically, with ab initio simulations, the ability of Li ions to enter a nanotube interior. While our calculations show that it is quite unlikely for the ions to pass through pristine nanotubes, they are much more likely to enter via large-sized topological defects consisting of at least 9- or more membered rings. It is unlikely that such defects are formed spontaneously, but it may be possible to induce such topological defects by violent non-equilibrium means such as ball milling, chemical means and/or ion bombardment. Indeed, recent experiments on ball milled nanotube samples do report an important increase in the Li ion uptake.

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