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<jats:p> <jats:italic>We investigate the adsorption of organic molecular semiconductor perylene on (7 × 7) reconstructed Si(111) surface by ultraviolet photoemission spectroscopy. It is observed that seven features that derive from the organic material are located at 0.71, 2.24, 4.0, 5.9, 7.46, 8.65 and 9.95 eV in binding energy. The theoretical calculation results reveal the most stable adsorption geometry of organic molecule perylene on Si(111) (7 × 7) substrates is at the beginning of deposition</jats:italic>.</jats:p>

<jats:p> <jats:italic>We investigate the effects of remote nitride-based plasma treatment on the channel carrier and device characteristics of AlGaN/GaN high electron mobility transistors (HEMTs). A 200 W NH<jats:sub>3</jats:sub>/N<jats:sub>2</jats:sub> remote plasma causes little degeneration of carrier mobility and an increase in electron density due to surface alteration, which results in a decrease in sheet resistance and an increase in output current by 20–30%. Improved current slump, suppressed gate leakage current, and improved Schottky contact properties are also achieved by using low-damage nitride-based plasma treatment. It is found that NH<jats:sub>3</jats:sub>/N<jats:sub>2</jats:sub> remote plasma treatment is a promising technique for GaN-based HEMTs to modulate the surface conditions and channel properties</jats:italic>.</jats:p>

<jats:p> <jats:italic>To improve the optical and electrical properties of AlGaN-based deep ultraviolet lasers, an inverse-trapezoidal electron blocking layer is designed. Lasers with three different structural electron blocking layers of rectangular, trapezoidal and inverse-trapezoidal structures are established. The energy band, electron concentration, electron current density, <jats:italic>P</jats:italic>–<jats:italic>I</jats:italic> and <jats:italic>V</jats:italic>–<jats:italic>I</jats:italic> characteristics, and the photoelectric conversion efficiency of different structural devices are investigated by simulation. The results show that the optical and electrical properties of the inverse-trapezoidal electron blocking layer laser are better than those of rectangular and trapezoidal structures, owing to the effectively suppressed electron leakage</jats:italic>.</jats:p>

<jats:p> <jats:italic>A stable and long-range antiferromagnetic (AFM) coupling without charge carrier mediators has been searched for a long time, but the existence of this kind of coupling is still lacking. Based on first principle calculations, we systematically study carrier free long-range AFM coupling in four transition metal chalcopyrite systems: ABTe<jats:sub>2</jats:sub> (A = Cu or Ag, B = Ga or In) in the dilute doping case. The AFM coupling is mainly due to the <jats:italic>p</jats:italic>–<jats:italic>d</jats:italic> coupling and electron redistribution along the interacting chains. The relatively small energy difference between <jats:italic>p</jats:italic> and <jats:italic>d</jats:italic> orbitals, as well as between dopants and atoms in the middle of the chain can enhance the stability of long-range AFM configurations. A multi-band Hubbard model is proposed to provide fundamental understanding of long-range AFM coupling</jats:italic>.</jats:p>

<jats:p> <jats:italic>We report the growth of ternary half-Heusler MnPtSn single crystals and detailed study on its structural and physical properties. MnPtSn single crystal has a larger lattice parameter than that in polycrystal and it exhibits antiferromagnetism with transition temperature <jats:italic>T</jats:italic> <jats:sub>N</jats:sub> at about 215 K, distinctly different from the ferromagnetism of MnPtSn polycrystal. Hall resistivity measurement indicates that the dominant carriers are hole-type and the nearly temperature-independent carrier concentration reaches about 2.86 × 10<jats:sup>22</jats:sup> cm<jats:sup>−3</jats:sup> at 5 K. Moreover, the carrier mobility is also rather low (4.7 cm<jats:sup>2</jats:sup>⋅V<jats:sup>−1</jats:sup>s<jats:sup>−1</jats:sup> at 5 K). The above results strongly suggest that the significant Mn/Sn anti-site defects, i.e., the content of Mn in MnPtSn single crystal, play a vital role on structural, magnetic and transport properties</jats:italic>.</jats:p>

<jats:p> <jats:italic>Single-walled carbon nanotubes (SWCNTs), due to their outstanding electrical and optical properties, are expected to have extensive applications, such as in transparent conductive films and ultra-small field-effect transistors (FETs). However, those applications can only be best realized with pure metallic or pure semiconducting SWCNTs. Hence, identifying and separating metallic from semiconducting SWCNTs in as-grown samples are crucial. In addition, knowledge of the type of an SWCNT is also important for further exploring its new properties in fundamental science. Here we report employing scanning near-field optical microscopy (SNOM) as a direct and simple method to identify metallic and semiconducting SWCNTs on SiO</jats:italic> <jats:sub>2</jats:sub> <jats:italic>/Si substrates. Metallic and semiconducting SWCNTs show distinct near-field optical responses because the metallic tubes support plasmons whereas the semiconducting tubes do not. The reliability of this method is verified using FET testing and Rayleigh scattering spectroscopy. Our result demonstrates that the SNOM technique provides a reliable, simple, noninvasive and in situ method to distinguish between metallic and semiconducting SWCNTs</jats:italic>.</jats:p>

<jats:p> <jats:italic>We report the formation of gold ramified aggregates after deposition of Au on an ionic liquid surface by thermal evaporation method at room temperature. It is observed that the aggregates are composed of both granules and nanocrystals with hexagonal or triangular appearances. The most probable size of the nanocrystals is much larger than that of the granules and it increases with the nominal deposition thickness. The formation mechanism of the granules, nanocrystals and aggregates is presented</jats:italic>.</jats:p>

<jats:p> <jats:italic>We study the effect of the initial-state energy variance to the short-time behavior of the Loschmidt echo (LE) in a purely dephasing model. We find that the short-time LE behaves as a Gaussian function with the width determined by the initial-state energy variance of the interaction Hamiltonian, while it is a quartic decaying function with the width determined by the initial-state energy variance of the commutator between the interaction Hamiltonian and the environmental Hamiltonian when the initial state is an eigenstate of the interaction Hamiltonian. Furthermore, the Gaussian envelope in the temporal evolution of LE in strong coupling regime is determined by the inband variance. We will also verify the above conclusion in the XY spin model (as environment).</jats:italic> </jats:p>

<jats:p> <jats:italic>We report the quantized superfluid vortex filaments induced by the axial flow effect, which exhibit intriguing loop structures on helical vortexes. Such new vortex filaments correspond to a series of soliton excitations including the multipeak soliton, W-shaped soliton, and anti-dark soliton, which have no analogue when the axial flow effect is absent. In particular, we show that the vortex filaments induced by the multipeak soliton and W-shaped soliton arise from the dual action of bending and twisting of the vortex, while the vortex filament induced by the anti-dark soliton is caused only by the bending action, which is consistent with the case of the standard bright soliton. These results will deepen our understanding of breather-induced vortex filaments and will be helpful for controllable ring-like excitations on vortices.</jats:italic> </jats:p>

<jats:p> <jats:italic>Based on velocity resonance and Darboux transformation, soliton molecules and hybrid solutions consisting of soliton molecules and smooth positons are derived. Two new interesting results are obtained: the first is that the relationship between soliton molecules and smooth positons is clearly pointed out, and the second is that we find two different interactions between smooth positons called strong interaction and weak interaction, respectively. The strong interaction will only disappear when <jats:italic>t</jats:italic> → ∞. This strong interaction can also excite some periodic phenomena.</jats:italic> </jats:p>