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Title of article :
Diffusion of a Ga adatom on the GaAs(001)‐c(4 × 4)‐heterodimer surface: A first principles study
Author/Authors :
Roehl، نويسنده , , J.L. and Aravelli، نويسنده , , S. and Khare، نويسنده , , S.V. and Phaneuf، نويسنده , , R.J.، نويسنده ,
Issue Information :
هفته نامه با شماره پیاپی سال 2012
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Abstract :
The adsorption and diffusion behavior of a Ga adatom on the GaAs (001)‐c(4 × 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 × 4)-heterodimer reconstruction surface were examined. A comparison with the c(4 × 4)-ss reconstruction was performed. Minimum energy sites (MES) on the c(4 × 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‐diffusion mechanisms were studied for relevant atoms. We observed a higher diffusion barrier for exchange mechanism compared to top hopping.
Keywords :
Density functional calculations , reconstruction , diffusion barriers , Adsorption , Gallium arsenide (001) surface
Journal title :
Surface Science
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