Surface energy of M2AC(0 0 0 1) determined by density functional theory (M = Ti, V, Cr; A = Al, Ga, Ge) |
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Authors: | D Music Z Sun JM Schneider |
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Institution: | a Materials Chemistry, RWTH Aachen University, Kopernikusstr. 16, D-52074 Aachen, Germany b Department of Physics, Condensed Matter Theory Group, Uppsala University, Box 530, S-751 21 Uppsala, Sweden |
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Abstract: | We have studied the correlation between the valence electron configuration and the electronic structure of M2AC(0 0 0 1) surfaces (M = Ti, V, Cr; A = Al, Ga, Ge) by density functional theory. The A surface termination is the most stable configuration for all systems studied according to our surface energy data. As the M valence electron population is increased, the surface energy increases by 22% and 12% for A = Al and Ga, respectively, while it decreases by 29% for A = Ge. This can be understood by evaluating the valence electron concentration induced changes in the surface density of states. Antibonding surface Md-Ap states are present as Ti is substituted by Cr in M2AC(0 0 0 1) for A = Al and Ga, while antibonding surface Md-Ap states are not present as Ti is substituted by Cr in M2GeC(0 0 0 1). |
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Keywords: | Density functional theory Surface energy Carbides |
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