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• he advent of EUV/X-ray FEL sources combined with instrumental advances have permitted to develop the nanoscale transient grating approach. - The performance of the two set-ups, designed and operated at FERMI, demonstrates significant research advances in condensed matter dynamics. • The EUV/soft x-ray transient grating method can be further exploited for addressing more exotic and unexplored matter properties. The development of ultra-bright extreme ultraviolet (EUV) and X-ray free electron laser (FEL) sources has enabled the extension of wave-mixing approaches into the short wavelength regime. Such a class of experiments relies upon nonlinear interactions among multiple light pulses offering a unique tool for exploring the dynamics of ultrafast processes and correlations between selected excitations at relevant length and time scales adding elemental and site selectivity as well. Besides the availability of a suitable photon source, the implementation of wave mixing methodology requires efforts in developing the instrumental set-up. We have realized at the FERMI FEL two dedicated set-ups to handle multiple FEL beams with preselected parameters in a non-collinear fashion and control their interaction sequence at the target. These unique apparatuses, combined with the exceptional characteristics of the seeded FERMI FEL, have allowed us to make the first steps into this field and further advances are foreseen in the near future. [ABSTRACT FROM AUTHOR]

Abstract: We have investigated the scattering mechanisms limiting the low-temperature electron mobility in unintentionally doped In0.75Al0.25As/In0.75Ga0.25As metamorphic quantum wells grown on GaAs (001) substrates. We found that the mobility is limited by background impurity scattering for densities lower than 2.0×1011 cm−2, and by the combination of this mechanism and alloy disorder scattering for higher densities. From such analysis we estimate an alloy disorder scattering potential of about 0.5±0.1eV. Moreover we show that when a strained InAs layer is located in the centre of the In0.75Ga0.25As well, the alloy disorder scattering can be reduced, yielding mobilities up to 320000cm2/Vs at a carrier concentration of 3.1×1011 cm−2. [Copyright &y& Elsevier]