The submonolayer growth by molecular beam epitaxy of InAs on the GaAs(001)-
(2x4) surface has been studied using rapid-quench scanning tunneling micros
copy. InAs islands exhibiting the (2x4) reconstruction are formed and show
remarkably similar characteristics to GaAs submonolayer homoepitaxy on this
surface. Detailed analysis of the islands indicates that strain plays a ne
gligible role in their nucleation, and the (2x4) reconstruction dominates b
oth island growth and island anisotropy.