Zinc-blende MnAs thin films directly grown on InP (001) substrates as possible source of spin-polarized current

We have directly grown zinc-blende (zb)-type MnAs thin films on InP (001) substrates without the aid of any buffer layer using molecular beam epitaxy (MBE). From the High-resolution X-ray diffraction (XRD) data, assuming face-centered cubic (fcc) MnAs structure, the average lattice constants values were calculated to be 6.068 and 6.060 Å for growth temperatures of 250 and 300 °C, respectively. High-resolution transmission electron microscopy (TEM) investigations and selected-area electron-diffraction (SAD) verified the successful growth of zb-type cubic MnAs coexisting with the NiAs-type hexagonal MnAs. The saturation magnetization was estimated to be 300 emu/cm3 determined from the magnetic field dependence of the magnetization curves. From the temperature dependence of magnetization, the Curie temperature was found to be approximately 308 K. Success in the growth of zb-type MnAs thin films could be reasonably explained by the existence of a monolayer of InAs at the interface between the MnAs and InP substrates.

► Zinc-blende-type MnAs films on InP (001) without any buffer layers.
► Calculation of lattice constants as average values of 6.068 and 6.060 Å.
► Zb-type MnAs thin film was clearly formed together with hexagonal-type MnAs.
► Success in the growth of zb-type MnAs could be explained by the existence of InAs.