Fabrication of a complex InAs ring-and-dot structure by droplet epitaxy

An InAs ring structure accompanying the formation of quantum dots (QDs) was fabricated on (1 0 0)GaAs using droplet epitaxy. The QDs were located in the vicinity of the ring, due to the diffusion of In atoms from the In droplets. In addition, the dots were found to have distributed elliptically and preferentially along the [0 1 1] direction, implying that In itself prefers to diffuse along the [0 1 1] direction, which is the opposite of the favorable diffusion orientation of group III atoms on (1 0 0)GaAs under a commonly used As-stabilized growth condition. This is the first observation of a ring structure accompanying the formation of quantum dots in droplet epitaxy.     

MD simulation study of the sputtering process by high-energy gas cluster impact

We performed molecular dynamics (MD) simulations to study the characteristic sputtering process with large cluster ion impact. The statistical properties of incident Ar and sputtered Si atoms were examined using 100 different MD simulations with Ar₁₀₀₀ cluster impacting on a Si(0 0 1) target at a total acceleration energy of 50 keV. The results show that the kinetic energy distribution of Ar atoms after impact obeys the high-temperature Boltzmann distribution due to thermalization through high-density multiple collisions on the target. On the other hand, the kinetic energy distribution of sputtered target atoms demonstrates a hybrid model of thermalization and collision-cascade desorption processes.     

Three-flavor quark mass dependence of baryon spectra in holographic QCD

We introduce the strange quark mass to the Sakai–Sugimoto model of holographic QCD. We compute mass shifts in the spectra of three-flavor baryons at the leading order in perturbation in quark masses. Comparison with experimental data shows an agreement only qualitatively.