Ab initio Investigation of the Early Stage of Nano-scale Thin Film Growth: Al and Co Adatoms on Co (111) Surface

摘要

We considered the diffusion behavior which occurred in the initial stages of thin film deposition for the fabrication of a tunneling magneto-resistance (TMR) junction with the use of the density functional theory (DFT). An Al adatom deposited on the Co (111) substrate had the most stable configuration when it was adsorbed on the hcp site and the energy barrier for the diffusion to the neighboring fcc or hcp site was sufficiently low for the Al adatom to move freely. The energy barrier for the Co on the Co substrate was approximately 1.6 times higher than that for the case of Al on a Co substrate. The energies for the step down (step energy barrier) of an adatom from the top of the adatom trimer were estimated as 0.54 eV and 1.09 eV for Al/ Al trimer/Co and Co/Co trimer/Co, respectively.