Research

"First-principles study of Cu(100)-c(2x2)N surface"

Cu(100)-c(2x2)N surface was studied by a first-principles calculation. On this surface, at appropriate N atom coverage, c(2x2)N islands take around 5nm squared size and are aligned into a regular square lattice separated by a square network of clean Cu surface lines. This self organized structure is used as a nano-size template to align magnetic materials.

On this system, recent experiments suggested 2-fold symmetric structure instead of the conventional 4-fold symmetric structure. The optimized structure had 4-fold symmetry. The simulated STM images supported the conventional understanding. In addition, the effective interaction energy among N atoms was calculated to understand the driving force of this self organization. The barrier height of the N atom was also estimated. For the calculation, a preconditioning method of SCF iteration was developed to save computational time.

[1] Y. Yoshimoto and S. Tsuneyuki, Int. J. Quant. Chem. 91, 211 (2002).
[2] Y. Yoshimoto and S. Tsuneyuki, Surf. Sci. 514, 200 (2002).

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