采用第一原理方法研究了Al终断(Al-terminated), O终断(O-terminated), Al2终断(Al2-terminated)的Ag/ \alpha -Al 2O3界面. 基于原子级热力学模拟,建立了Ag/Al2O3界面结构与O2分压关系. 分别采用了参考Al化学势和参考O化学势作为环境变量的两种近似处理方法, 发现它们预测的从Al终断向O终断转变的氧分压点相差约4个数量级. 通过对界面热容的估算,判断出更准确的结果应在两个近似之间, 而且用Al化学势作参照的结果应与实验结果更接近. Ag/Al2O3界面结构与O2分压的关系与文献报道的相应润湿性(wetting)实验具有同样的趋势. 理论预测的结构转变点与实验结果的误差在合理的范围内.
Ag/ α-Al2O3 interfaces of O-, Al-, and Al2-termination were calculated by an ab initio method. The dependence of the stability of the interfaces on O2 partial pressure at 1300K was built through the so-called ab initio thermodynamics. Two approaches were performed to bridge the gap between ab initio calculation and real experimental condition, corresponding to analyzing data based on either Al chemical potential or O chemical potential respectively. The approaches caused a 4 order of magnitude difference of the O2 partial pressure at which interfacial structure transits from Al-termination to O-termination. Further analysis shows that the real transitional point should fall in between the results from the two approaches, and the result based directly on Al chemical potential is closer to the real point. Our results show the same trend of interfacial stability in comparision with the reported wetting experiments, and the predicted transitional points for different terminations are also close to
experimental one.
参考文献
| [1] | Zhang W, Smith J R, Wang X G. Phys. Rev. B, 2004, 70 (2): 024103--1--8. [2] Zhang W, Smith J R, Evans A G. Acta Mater, 2002, 50 (15): 3803--3816. [3] Chatain D, Chabert F, Ghetta V, et al. J. Am. Ceram Soc, 1994, 77 (1): 197--201. [4] Zhukovskii Yu F, Kotomin E A, Herschend B, et al. Surf. Sci, 2002, 513 (2): 343--358. [5] Zhang W, Smith J R. Phys. Rev. Lett., 2000, 85 (15): 3225--3228. [6] Ralph W G. Wyckoff. Crystal Structures Volume 2, Second Edition. New York: Interscience, 1964. 7--8. [7] Kresse G, Furthm \ddot u ller J. Phy. Rev. B, 1996, 54 (16): 11169--11186. [8] Kresse G, Hafner J. Phys. Rev. B, 1993, 47 (1): 558--561. [9] Kresse G, Hafner J. J. Phys. Condens. Matter, 1994, 6 (40): 8245--8257. [10] Vanderbilt D. Phys. Rev. B, 1990, 41 (11): 7892--7895. [11] Perdew J P. Electronic Structure of Solids ’91, Edited by Ziesche P and Eschrig H. Berlin:Akademie Verlag, 1991. 11--20. [12] Monkhorst H J, Pack J D. Phys. Rev. B, 1976, 13 (12): 5188--5892. [13] Chase M W, Davies C A, Downey J R, et al. JANAF Thermochemical Tables, 3rd Ed. J. Phys.Chem. Ref. Data, 1985, 14(Supplement No.1) [14] Batyrev Iskander G, Alavi Ali, Finnis M W. Phys. Rev. B, 2000, 62 (7): 4698--4706. [15] Li W X, Stampfl C, Scheffler M. Phys. Rev. Lett., 2003, 90 (25): 256102--1--4. |
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