Abstract:   The ability to integrate dissimilar materials with different crystal structures and properties enables heterostructures to be developed with new functionality well beyond the normal band gap engineering offered by semiconductor heterostructures. The combination of metals, semiconductors, insulators, magnetic, piezoelectric, structural and phase change materials offers the potential for nearly limitless control of device properties. Heusler compounds, for example, are of great interest due to their multifunctional properties including metallic, ferromagnetic, half metallic, semiconducting and potentially topological properties. Heterostructures of ferromagnetic materials with insulators and semiconductors have revolutionized spintronic devices.

Semiconductors are an ideal choice for substrates for dissimilar materials epitaxial growth because of their wide range of lattice parameters, high quality, readily controlled electrical and optical properties and the availability of large area substrates at a reasonable cost. The control of strain and lattice matching, interfacial bonding and reactions is important for the growth and properties of dissimilar materials heterostructures.

In this presentation, results for the molecular beam epitaxial growth of metallic compound/III-V semiconductor heterostructures with designer properties will be discussed. High efficiency electrical spin injection and detection in magnetic Heusler/GaAs contacts, tuning of the spin polarization, as well as the ability to tune the electronic and magnetic properties of Heusler compounds through alloying will be presented. The focus of the presentation will be on understanding the growth and properties of dissimilar materials with emphasis on Heusler compound/III-V compound semiconductor heterostructures. These studies have aimed at tailoring of interfacial and material properties of these dissimilar materials heterostructures for targeting novel applications including spintronics and topological quantum computing.