Atomistic mechanisms of fracture accompanying structural phase transformation (SPT) in AlN ceramic under hypervelocity impact are investigated using a 209 x 10(6) atom molecular-dynamics simulation. The shock wave generated by the impact splits into an elastic wave and a slower SPT wave that transforms the wurtzite structure into the rocksalt phase. The interaction between the reflected elastic...

An ab initio study of nitride-based heteroepitaxial interfaces that uses norm-conserving pseudopotentials and explicitly treats the strain due to lattice mismatch is presented. Strain effects on the band offsets range from 20% to 40%. The AlN/GaN/InN interfaces ~with AlN in-plane lattice constant! are all of type I, while the Al 0.5Ga0.5N/AlN zinc-blende ~001! interface is of type II. Further, ...

The pressure-dependent phonon modes of InAs nanowires have been investigated by Raman spectroscopy under high pressure up to ∼58 GPa. X-ray diffraction measurements show that InAs nanowires at 21 GPa exhibit a phase transition from a wurtzite to an orthorhombic crystal structure, with a corresponding drastic change in the first-order Raman spectra. In the low-pressure regime, a linear increase ...

Measurements of the diffuse X-ray scattering intensity are performed from the (100), (010) and (001) planes in the AgInS2 ternary compound with the orthorhombic wurtzite-type structure. From these data all nine elastic moduli Cik as well as the phase velocities of the elastic waves along different crystallographic directions for longitudinal and transverse polarizations are found. A comparative...

The results of an accurate theoretical study on the effects of non-abrupt doping and interfacial profiles on the electron sheet density in one-side modulation-doped wurtzite GaN/AlGaN single quantum wells at low temperatures are presented. We solve coupled Schrödinger and Poisson equations self-consistently via the finite difference method. By employing a proper discretization on a nonuniform g...

Wurtzite ZnO hexagonal micro-pyramids, with all exposed surfaces being polar +/- (0001) and {1011} planes, have been successfully synthesized using ionic liquids as solvents.