Electronic stability of magnetic Fe/Co superlattices with monatomic layer alternation
Farnan GA, Fu CL, Gai Z, Krcmar M, Baddorf AP, Zhang ZY, Shen J
PHYSICAL REVIEW LETTERS
91 (22): Art. No. 226106 NOV 28 2003
We report a surprising observation that the growth of the [Fe(1 ML)/Co(1 ML)](n) superlattice of L1(0) structure on Cu(100) is stable only up to six atomic layers (n=3), which cannot be rationalized by stress arguments. Instead, first-principles calculations reveal a transition from the L1(0) to the B2 structure due to the effect of dimensionality on the stability of the electronic structure of the superlattice. Whereas the majority-spin electrons are energetically insensitive to the layer thickness, the minority-spin electrons induce the transition at n=3.