The nanohardness and Young's modulus of PbCdTe single crystals prepared by the self-selecting vapor growth (SSVG) method and thick, MBE-grown layers with a total Cd content of up to 7% metal atoms were studied using the nanoindentation technique; the nanohardness and Young's modulus were calculated by the Oliver and Pharr method. Significant hardening of SSVG crystals with increasing number of Cd atoms replacing Pb atoms in the formed solid solution was observed, and low anisotropy of the nanohardness and Young's modulus were found. The CdTe solubility limit in the solid solution grown using an MBE equal to 2.
View Article and Find Full Text PDFAn arrangement of self-assembled GaN nanowires (NWs) grown by plasma-assisted molecular beam epitaxy on a Si(111) substrate is studied as a function of the temperature at which the substrate is nitridized before GaN growth. We show that the NWs grow with the c-axis perpendicular to the substrate surface independently of nitridation temperature with only a slight improvement in tilt coherency for high nitridation temperatures. A much larger influence of the substrate nitridation process on the in-plane arrangement of NWs is found.
View Article and Find Full Text PDFTopological insulators are a class of quantum materials in which time-reversal symmetry, relativistic effects and an inverted band structure result in the occurrence of electronic metallic states on the surfaces of insulating bulk crystals. These helical states exhibit a Dirac-like energy dispersion across the bulk bandgap, and they are topologically protected. Recent theoretical results have suggested the existence of topological crystalline insulators (TCIs), a class of topological insulators in which crystalline symmetry replaces the role of time-reversal symmetry in ensuring topological protection.
View Article and Find Full Text PDFGaAs:Mn nanowires were obtained on GaAs(001) and GaAs(111)B substrates by molecular beam epitaxial growth of (Ga,Mn)As at conditions leading to MnAs phase separation. Their density is proportional to the density of catalyzing MnAs nanoislands, which can be controlled by the Mn flux and/or the substrate temperature. After deposition corresponding to a 200 nm thick (Ga,Mn)As layer the nanowires are around 700 nm long.
View Article and Find Full Text PDFThe molecular mechanism of cell death induced by AGS 115 and EFDAC, sesquiterpene analogs of paclitaxel, was investigated in human breast cancer MCF-7 cells. The study was carried out using laser scanning cytometry, homeostatic confocal microscopy, atomic force microscopy and electron microscopy. AGS 115 and EFDAC exhibited a microtubule-stabilizing effect as confirmed by a significant increase in alpha-tubulin aggregation.
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