Diffusion of a Ga adatom on the GaAs(001)鈥?span style='font-style: italic'>c(4 脳 4)鈥恏eterodimer surface: A first principles study

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• 作者：J.L. Roehl^a ; S. Aravelli^b ; S.V. Khare^a ; ^{sanjay.khare@utoledo.edu} ; R.J. Phaneuf^c
• 关键词：Gallium arsenide (001) surface ; Adsorption ; Diffusion barriers ; Reconstruction ; Density functional calculations
• 刊名：Surface Science
• 出版年：2012
• 期刊代码：104_00396028
• 类别：ch
• 出版时间：August, 2012
• 卷：606
• 期：15-16
• 页码：1303-1307
• 文件大小：694 K

摘要

The adsorption and diffusion behavior of a Ga adatom on the GaAs (001)鈥?em>c(4 脳 4)-heterodimer surface were studied by employing ab initio density functional theory (DFT) computations in the local density approximation. Structural and bonding features of the c(4 脳 4)-heterodimer reconstruction surface were examined. A comparison with the c(4 脳 4)-ss reconstruction was performed. Minimum energy sites (MES) on the c(4 脳 4)-heterodimer surface were located by mapping the potential energy surface for a Ga adatom. Barriers for diffusion of a Ga adatom between the neighboring MES were calculated by using top hopping- and exchange-diffusion mechanisms. We proposed two unique diffusion pathways for a Ga adatom diffusing between the global minimums of two neighboring unit cells. Signature differences between electronic structures of top hopping- and exchange鈥恉iffusion mechanisms were studied for relevant atoms. We observed a higher diffusion barrier for exchange mechanism compared to top hopping.