First Principles Calculations for Metal/Ceramic Interfaces

MRS Proceedings ◽

10.1557/proc-357-427 ◽

1994 ◽

Vol 357 ◽

Cited By ~ 2

Author(s):

M. W. Finnis ◽

C. Kruse ◽

U. SchÖnberger

Keyword(s):

Electronic Structure ◽

High Resolution ◽

Ab Initio ◽

First Principles ◽

Density Functional ◽

Local Density ◽

Work Of Adhesion ◽

First Principles Calculations ◽

Resolution Electron ◽

Metal Ceramic

AbstractWe discuss the recent first principles calculations of the properties of interfaces between metals and oxides. This type of calculation is parameter-free, and exploits the density functional theory in the local density approximation to obtain the electronic structure of the system. At the same time the equilibrium atomic structure is sought, which minimises the excess energy of the interface. Up to now calculations of this type have been made for a few model interfaces which are atomically coherent, that is with commensurate lattices. Examples are Ag/MgO and Nb/Al2O3. In these cases it has been possible to predict the structures observed by high resolution electron microscopy. The calculations are actually made in a supercell geometry, in which there are alternating nanolayers of metal and ceramic. Because of the effectiveness of metallic screening in particular, the interfaces between the nanolayers do not interfere much with each other.Besides the electronic structure of the interface, such calculations have provided values of the ideal work of adhesion. Electrostatic image forces in conjunction with the elementary ionic model provide a simple framework for understanding the results.An important role of such calculations is to develop intuition about the nature of the bonding, including the effects of charge transfer, which has formerly only been described in an empirical way. It may then be possible to build atomistic models of the metal/ceramic interaction which have a sound physical basis and can be calibrated against ab initio results. Simpler models are necessary if larger systems, including misfit dislocations and other defects, are to be simulated, with a view to understanding the atomic processes of growth and failure. Another area in which ab initio calculations can be expected to contribute is in the chemistry of impurity segregation and its effect at interfaces. Such theoretical tools are a natural partner to the experimental technique of high resolution electron energy loss spectroscopy for studying the local chemical environment at an interface.

Download Full-text

Magnetic Properties of Embedded Rh Clusters in Ni Matrix

MRS Proceedings ◽

10.1557/proc-384-535 ◽

1995 ◽

Vol 384 ◽

Author(s):

Zhi-Qiang Li ◽

Yuichi Hashi ◽

Jing-Zhi Yu ◽

Kaoru Ohno ◽

Yoshiyuki Kawazoe

Keyword(s):

Magnetic Properties ◽

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Local Density ◽

Magnetic Moments ◽

Functional Formalism ◽

Rhodium Clusters ◽

Spin Polarized ◽

Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

Download Full-text

Structural, elastic and thermodynamic properties of A15-type compounds V3X (X = Ir, Pt and Au) from first-principles calculations

Modern Physics Letters B ◽

10.1142/s0217984916504145 ◽

2016 ◽

Vol 30 (35) ◽

pp. 1650414 ◽

Cited By ~ 6

Author(s):

Mingliang Wang ◽

Zhe Chen ◽

Dong Chen ◽

Cunjuan Xia ◽

Yi Wu

Keyword(s):

Thermodynamic Properties ◽

Debye Temperature ◽

First Principles ◽

Density Functional ◽

Coefficient Of Thermal Expansion ◽

Local Density ◽

Debye Model ◽

First Principles Calculations ◽

Generalized Gradient ◽

Experimental Values

The structural, elastic and thermodynamic properties of the A15 structure V3Ir, V3Pt and V3Au were studied using first-principles calculations based on the density functional theory (DFT) within generalized gradient approximation (GGA) and local density approximation (LDA) methods. The results have shown that both GGA and LDA methods can process the structural optimization in good agreement with the available experimental parameters in the compounds. Furthermore, the elastic properties and Debye temperatures estimated by LDA method are typically larger than the GGA methods. However, the GGA methods can make better prediction with the experimental values of Debye temperature in V3Ir, V3Pt and V3Au, signifying the precision of the calculating work. Based on the E–V data derived from the GGA method, the variations of the Debye temperature, coefficient of thermal expansion and heat capacity under pressure ranging from 0 GPa to 50 GPa and at temperature ranging from 0 K to 1500 K were obtained and analyzed for all compounds using the quasi-harmonic Debye model.

Download Full-text

Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

Canadian Journal of Physics ◽

10.1139/p06-008 ◽

2006 ◽

Vol 84 (2) ◽

pp. 115-120 ◽

Cited By ~ 3

Author(s):

G Y Gao ◽

K L Yao ◽

Z L Liu

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Exchange Correlation ◽

Pseudopotential Calculations ◽

Correlation Potential ◽

Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

Download Full-text

First-principles study of static displacements in Fe-Pd magnetic shape-memory alloys

MRS Proceedings ◽

10.1557/proc-1200-g04-04 ◽

2009 ◽

Vol 1200 ◽

Cited By ~ 1

Author(s):

Markus E. Gruner

Keyword(s):

Density Functional Theory ◽

Electronic Structure ◽

First Principles ◽

Density Functional ◽

First Principles Calculations ◽

Magnetic Shape Memory ◽

Magnetic Shape Memory Alloys ◽

Functional Theory ◽

Lennard Jones ◽

Theory Comparison

AbstractThis contribution reports static ionic displacements in ferromagnetic disordered Fe70Pd30 alloys obtained by relaxation of the ionic positions of a 108-atom supercell within the framework of density functional theory. Comparison with a simple statistical model based on Lennard-Jones pair interactions reveals that these displacements are significantly larger than can be explained by the different sizes of the elemental constituents. The discrepancies are presumably related to collective displacements of the Fe atoms. Corresponding distortions are experimentally observed for ordered Fe3Pt and predicted by first-principles calculations for all ordered Fe-rich L12 alloys with Ni group elements and originate from details of the electronic structure at the Fermi level.

Download Full-text

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

Physical Chemistry Chemical Physics ◽

10.1039/c7cp01359k ◽

2017 ◽

Vol 19 (23) ◽

pp. 15021-15029 ◽

Cited By ~ 7

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).

Download Full-text

First-principles Study of the Electronic Structure and Local Moment Interactions in PuAm Alloy

MRS Proceedings ◽

10.1557/proc-1104-nn02-08 ◽

2008 ◽

Vol 1104 ◽

Author(s):

Myung Joon Han ◽

Xiangang Wan ◽

Sergej Y Savrasov

Keyword(s):

Electronic Structure ◽

First Principles ◽

Local Density ◽

Exchange Interactions ◽

Kondo Lattice ◽

First Principles Calculations ◽

Correlation Effects ◽

Self Consistent ◽

5F Electrons ◽

Zero Moment

AbstractExpected to provide a clue about the origin of zero moment in the bulk phase of Plutonium, Pu1-xAmx alloys have attracted a great attention, in which upon doping the system transforms from the Kondo lattice to the diluted impurity limit. To understand the electronic structure and the magnetic properties of Pu in different crystal environments, we performed fully self-consistent first-principles calculations of the PuAm system based on the local density approximation (LDA) combined with static (LDA+U) and dynamic corrections (LDA+DMFT) for on-site electron correlations. The electronic structure strongly depends on the level of approximation for correlation effects. The exchange interactions between Pu 5f electrons and the Kondo screening strength were estimated and compared, which provide a new insight to Pu magnetism.

Download Full-text

First Principles Calculations of Electronic Structure and Optical Properties of Cu-Doped SnS2

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.373-375.1965 ◽

2013 ◽

Vol 373-375 ◽

pp. 1965-1969

Author(s):

Kun Nan Qin ◽

Ling Zhi Zhao ◽

Yong Mei Liu ◽

Fang Fang Li ◽

Chao Yang Cui

Keyword(s):

Optical Properties ◽

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Optical Absorption Coefficient ◽

Impurity Level ◽

First Principles Calculations ◽

Absorption Region ◽

Functional Theory ◽

The Density Functional Theory

The electronic structure and optical properties of Cu-doped SnS2with Sn-substituted content of 0, 12.5 and 37.5 at.% were successfully calculated by the first principles plane-wave pseudopotentials based on the density functional theory. It is found that the intermediate belts appear near the Fermi level and the energy band gap becomes narrower after the doping of the Cu atoms. The absorption peaks show a remarkable redshift and the absorption region broadens relatively after introducing acceptor impurity level. When Sn atoms of 37.5 at% were substituted by Cu, the optical absorption coefficient is significantly improved in the frequency range below 5.58 eV and over 8.13 eV.

Download Full-text

THEORETICAL INVESTIGATION OF THE ELASTIC PROPERTIES AND LATTICE DYNAMICS OF THE MgSxSe1-x ALLOY

Modern Physics Letters B ◽

10.1142/s0217984907012621 ◽

2007 ◽

Vol 21 (05) ◽

pp. 249-259 ◽

Cited By ~ 9

Author(s):

K. BOUAMAMA ◽

P. DJEMIA

Keyword(s):

Elastic Properties ◽

First Principles ◽

Lattice Dynamics ◽

Density Functional ◽

Local Density ◽

Lattice Parameter ◽

First Principles Calculations ◽

Virtual Crystal Approximation ◽

Functional Theory ◽

Density Functional Perturbation Theory

Structural and elastic properties as well as lattice dynamics of ternary MgS x Se 1-x alloy have been studied using first-principles calculations. These are done using density functional theory (DFT) and density functional perturbation theory (DFPT) within the local density approximation (LDA) and employing the virtual-crystal approximation (VCA). We found that the lattice parameter, the elastic constants and the phonon frequencies follow a quadratic law in x.

Download Full-text

Electronic Structure and Hydrogen Desorption in NaAlH4

MRS Proceedings ◽

10.1557/proc-837-n2.5 ◽

2004 ◽

Vol 837 ◽

Cited By ~ 1

Author(s):

S. Li ◽

P. Jena ◽

C. M. Araujo ◽

R. Ahuja

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Metal Hydrides ◽

Hydrogen Desorption ◽

Light Metal ◽

First Principles Calculations ◽

Functional Theory ◽

Design And Synthesis

ABSTRACTFirst principles calculations based on gradient corrected density functional theory are carried out to understand the electronic structure and mechanisms responsible for desorption of hydrogen from Ti doped and vacancy containing sodium-alanate (NaAlH4). The energy necessary to remove a hydrogen atom from Ti doped NaAlH4 is significantly smaller than that from pristine NaAlH4 irrespective of whether Ti substitutes the Na or the Al site. However, the presence of Na and Al vacancies is shown to play an even more important role: The removal of hydrogen associated with both Na and Al vacancies is found to be exothermic. It is suggested that this role of vacancies can be exploited in the design and synthesis of complex light metal hydrides suitable for hydrogen storage.

Download Full-text

First-principles Calculations of Energetic Properties of Vacancies, Mn-atomic Defects in CdTe

MRS Proceedings ◽

10.1557/proc-0959-m17-01 ◽

2006 ◽

Vol 959 ◽

Author(s):

Ghouti Merad ◽

Benali Rerbal ◽

Hafid Aourag ◽

Joël Cibert

Keyword(s):

Density Functional Theory ◽

First Principles ◽

Density Functional ◽

Local Density ◽

Density Approximation ◽

First Principles Calculations ◽

Functional Theory ◽

Energetic Properties ◽

Atomistic Modelling ◽

Atomic Type

ABSTRACTAn atomistic modelling based on density functional theory within the framework of the local density approximation is used to show the trends in the energetic properties of single and double defects in CdTe semiconductor, without phase transformation. A systematic study of vacancies, Mn substituting Cd atoms in a supercell structure consisting of 16-atoms is presented. The changes of structural properties and lattice parameters due to the addition of Mn-atomic type defects in CdTe matrix are compared, and the number of vacancies is also determined from the total energy calculations.

Download Full-text