Effects of finite temperature on the surface energy in Al alloys from first-principles calculations

Surface energies of strained Cu surfaces were studied systematically using first-principles methods. Results showed that the strain-stabilization of Cu surface was anisotropic and strongly related to the strain distribution. This strain-induced approach could be used as an effective way to engineer the surface energies of metals.

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First Principles Calculations for Alloy Design of Moderate Temperature Age-Hardenable Al Alloys

Materials Science Forum - Aluminium Alloys 2006 ◽

10.4028/0-87849-408-1.35 ◽

2006 ◽

pp. 35-44

Author(s):

Ai Wu Zhu ◽

Gary J. Shiflet ◽

E.A. Jr. Starke

Keyword(s):

First Principles ◽

Al Alloys ◽

Alloy Design ◽

Moderate Temperature ◽

First Principles Calculations

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First-Principles Study of Nanofacet Formation on 4H-SiC(0001) Surface

Materials Science Forum ◽

10.4028/www.scientific.net/msf.778-780.201 ◽

2014 ◽

Vol 778-780 ◽

pp. 201-205

Author(s):

Keisuke Sawada ◽

Jun Ichi Iwata ◽

Atsushi Oshiyama

Keyword(s):

Surface Energy ◽

Total Energy ◽

First Principles ◽

Atomic Layer ◽

First Principles Calculations ◽

Atomic Structures ◽

First Principles Study ◽

Energy Variation ◽

The Difference ◽

Facet Formation

We perform the first-principles calculations on the 4H-SiC(0001) surface and clarify the mechanism of the facet formation. We first identify atomic structures of single-, double- and quadribilayer steps and find that the single-bilayer (SB) step has the lowest total energy among these three step structures. Then, we reveal that the nanofacet consisting of SB steps is more energetically stable than the equally spaced SB step and the surface-energy variation caused by the difference of stacking sequences of the bi-atomic layer near the surface is an important factor of the facet formation.

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New high pressure polymorph of the CaSi2 compound with Laves structure

Modern Physics Letters B ◽

10.1142/s0217984914500808 ◽

2014 ◽

Vol 28 (10) ◽

pp. 1450080

Author(s):

Hichem Bouderba ◽

Raouf Beddiaf

Keyword(s):

High Pressure ◽

First Principles ◽

Finite Temperature ◽

First Principles Calculations ◽

Laves Phases

In the present work, based on first-principles calculations, we show that it is possible to obtain a new high pressure polymorph of the CaSi 2 compound with a Laves structure. It corresponds to the MgCu 2-type (C15) which is one of the three most important Laves phases. We also show that the two other structures, MgNi 2- and MgZn 2-types are very competitive energetically and are possible candidates for finite temperature investigations.

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The Influence of Surface Reconstruction and C-impurities on Photocatalytic Water Dissociation by TiO2

MRS Proceedings ◽

10.1557/proc-801-bb6.6 ◽

2003 ◽

Vol 801 ◽

Cited By ~ 3

Author(s):

Xiliang Nie ◽

Karl Sohlberg

Keyword(s):

Surface Energy ◽

Band Gap ◽

First Principles ◽

Active Sites ◽

Water Dissociation ◽

First Principles Calculations ◽

Surface Band ◽

Carbon Doped ◽

Carbon Impurities ◽

Photoabsorption Spectrum

ABSTRACTTiO2 is well known as a prototype photocatalyst for water dissociation. To understand the mechanism of its photocatalytic water dissociation we performed first-principles calculations. We find that the surface of the catalytically favorable (TiO) termination is very different from the physically favorable (oxygen) termination. The calculated surface energy of the catalytically favorable (TiO) termination is about 10 times larger than that of the physically favorable (oxygen) termination. Analysis of the surface band structure suggests that while O-vacancies are intrinsic active sites for water dissociation into H2 and O2 gas, they are not essential for photocatalytic water dissociation. We also find that carbon impurities decrease the band-gap of TiO2, in agreement with previously reported experimental results. Moreover, we identify the origin of the arcane “double band gap” in carbon doped TiO2. The two onsets seen in the photoabsorption spectrum result from excitations from two of three C p-states within the band gap, not from domains of different composition.

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