SPIN ORBIT INDUCED ORBITAL ANGULAR-MOMENTUM IN MONOLAYERS

We calculate spin-orbit induced orbital angular momentum in ferromagnetic monolayers of Fe, Co and Ni. For Fe the induced momentum is moderate leading to a spectroscopic splitting factor of 2.06. This is slightly smaller than the value 2.09 measured in bulk Fe. Values in this range are also observed in Fe overlayers on inert substrates. For Co the induced momentum is larger and gives a spectroscopic splitting factor of 2.25, somewhat larger than the bulk Co value of 2.19. For Ni the induced momentum is large: comparable to the spin moment itself. This leads to a prediction of spectroscopic splitting factors as large as 3.06 (for a monolayer with the lattice constant of Ag). Bulk Ni is 2.18. No measurements of the spectroscopic splitting factor for Co or Ni overlayers have been reported.