Mn5ge3 Ultra-Thin Films On Gaas (111)B Substrates: Influence Of Initial Growth Conditions

We report the interaction of Mn5Ge3 ultra-thin films with GaAs (111)B substrates under distinct initial conditions by monitoring in-situ the in-plane crystal structure and surface chemistry using reflection high energy electron diffraction and X-ray photoelectron spectroscopy. The order of Mn and Ge adatoms arriving on the GaAs surface determines the interface elemental stoichiometry, crystalline quality, and films thermal stability. When the growth starts by opening the Mn and Ge cells simultaneously is sufficient to inhibit the strong reactions with the GaAs (111) surface. First principles calculations show that the Mn5Ge3 epitaxial growth on the GaAs (111)B is feasible, with a lattice mismatch of 2.3% which is in agreement with the value of at least 2.6% estimated within the accuracy of our RHEED measurements. Results have implications in the design of MBE growth strategies to achieve Mn5Ge3/GaAs semiconductor heterostructure.