Low-index surface energies, cleavage energies, and surface relaxations for crystalline NiAl from first-principles calculations

Journal Article · 05 November 2019 · Surface Science

DOI: https://doi.org/10.1016/j.susc.2019.121532 · OSTI ID:1606247

Wang, Linxia ^[1]; Lai, King C. ^[2]; Huang, Li ^[3]; Evans, James W. ^[2]; Han, Yong ^[2]

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1. Southern Univ. of Science and Technology, Shenzhen (People's Republic of China); Naikai Univ., Tianjin, (People's Republic of China)
2. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
3. Southern Univ. of Science and Technology, Shenzhen (People's Republic of China)

NiAl surfaces frequently serve as a platform for studying a broad range of physical and chemical phenomena including chemisorption, catalysis, oxidation, alloy growth, and surface nanostructure formation. Knowledge of precise values for low-index surface energies of NiAl, the most fundamental quantities characterizing surface thermodynamics, is often invaluable for understanding of these phenomena. In all previous analyses for NiAl(100) and NiAl(111), Ni- and Al-terminations are not distinguished, and half of the cleavage energy (or equivalently, the average of the surface energies of two differently terminated surfaces) is always identified as the “surface energy”. No values are available for individual surface energies of Ni- or Al-terminated NiAl(100) or NiAl(111) surfaces, whereas knowledge of only cleavage energy is often insufficient for analyzing surface-associated behavior. As such, in this work we perform extensive first-principles density-functional-theory (DFT) calculations for surface energies and cleavage energies of NiAl(110), NiAl(100) and NiAl(111) by considering the chemical-potential-based formulations to clarify the ambiguity in their surface energies and cleavage energies. We obtain a surface-energy phase diagram for these three low-index surfaces versus the relevant chemical potential, as well as the chemical-potential-dependent Wulff plots for NiAl crystal equilibrium shapes. We also provide the surface-relaxation information from our DFT calculations for comparison with previous experimental data.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
• Sponsoring Organization: National Natural Science Foundation of China (NSFC); National Science Foundation (NSF); Shenzhen Basic Research Fund; USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
• Grant/Contract Number: AC02-05CH11231; AC02-07CH11358
• OSTI ID: 1606247
• Report Number(s): IS--J-10,178; SUSC_2019_665
• Journal Information: Surface Science, Journal Name: Surface Science Journal Issue: C Vol. 695; ISSN 0039-6028
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English