DFT study on termination stabilities of Mg17Al12 (110) surface
(1. College of Mechanics and Materials, Hohai University, Nanjing 210098, China;
2. College of Science, Hohai University, Nanjing 210098, China)
2. College of Science, Hohai University, Nanjing 210098, China)
Abstract: The Mg17Al12 (110) surface has five possible terminations (T1-T5). The T3 termination has been regarded as the most stable termination for long time, whereas recent theoretical calculations have revealed that the T1 termination is the most stable one. To solve the dispute, density functional theory calculations were performed in this study to unravel the most stable termination of Mg17Al12 (110) surface. Surface energy calculation results show that, whether defects are considered or not, the T1 termination is always the most stable termination of Mg17Al12 (110) surface. The stability of T1 termination may be ascribed to the Al truncated-tetrahedron because only cutting Mg17Al12 along T1 termination of (110) surface will not destroy the integrity of Al truncated-tetrahedron. In addition to unraveling the most stable termination, work functions of Mg17Al12 (110) surface were also calculated. The results show that the work function of Mg17Al12 (110) surface is mainly controlled by concentration of surface AlMg defects.
Key words: Mg17Al12; surface termination; density functional theory; surface energy; work function