Hole-mediated interactions of Mn acceptors on GaAs (110) (invited)

A scanning-tunneling-microscopy-substitution technique is used to incorporate single Mn atoms into Ga sites in GaAs (110) surfaces. The electronic states near a single Mn in the acceptor configuration produce a strong in-gap resonance associated with the acceptor level. The isolated Mn acceptor is probed in both p -type and n -type environments to access the neutral and ionized acceptor configurations. The Mn acceptor at the surface substitution site shares bulk characteristics that compare well with tight-binding calculations. The anisotropic structure of the Mn hole state plays an important role in hole-mediated interactions between the Mn acceptors. Isolated Mn pairs show a strong interaction dependence on crystal orientation and spacing. Certain pair orientations produce a strong splitting of the acceptor level into two levels with bondinglike and antibondinglike symmetries. A tight-binding model relates the acceptor level splitting and the spin-spin interaction energy J.