131 research outputs found
Pressure induced superconductivity bordering a charge-density-wave state in NbTe4 with strong spinorbit coupling
Transition-metal chalcogenides host various phases of matter, such as
charge-density wave (CDW), superconductors, and topological insulators or
semimetals. Superconductivity and its competition with CDW in low-dimensional
compounds have attracted much interest and stimulated considerable research.
Here we report pressure induced superconductivity in a strong spin-orbit (SO)
coupled quasi-one-dimensional (1D) transition-metal chalcogenide NbTe,
which is a CDW material under ambient pressure. With increasing pressure, the
CDW transition temperature is gradually suppressed, and superconducting
transition, which is fingerprinted by a steep resistivity drop, emerges at
pressures above 12.4 GPa. Under pressure = 69 GPa, zero resistance is
detected with a transition temperature = 2.2 K and an upper critical
field = 2 T. We also find large magnetoresistance (MR) up to 102\% at
low temperatures, which is a distinct feature differentiating NbTe from
other conventional CDW materials.Comment: https://rdcu.be/LX8
Quantum Well Laser Diodes With Slightly-Doped Tunnel Junction
We experimentally investigate the electrical and optical characteristics of conventional quantum well laser diodes and the quantum well laser diodes with slightly-doped tunnel junction N++GaAs/undoped-GaAs. The results show that the slightly-doped tunnel junction give significant role on the laser diodes performances in the InGaAs/GaAs quantum well material system. The TJ LD has a internal quantum efficiency of 21% and the loss is 6.9 em -1 , the current threshold is 35 mA, both the lasers are operating at 1.06 μm, but the slightly-doped tunnel junction diode show nonlinear S-shaped current-voltage and broadband lasing characteristics. The results may also lead to the realization of more applications
FIRST: A Million-Entry Dataset for Text-Driven Fashion Synthesis and Design
Text-driven fashion synthesis and design is an extremely valuable part of
artificial intelligence generative content(AIGC), which has the potential to
propel a tremendous revolution in the traditional fashion industry. To advance
the research on text-driven fashion synthesis and design, we introduce a new
dataset comprising a million high-resolution fashion images with rich
structured textual(FIRST) descriptions. In the FIRST, there is a wide range of
attire categories and each image-paired textual description is organized at
multiple hierarchical levels. Experiments on prevalent generative models
trained over FISRT show the necessity of FIRST. We invite the community to
further develop more intelligent fashion synthesis and design systems that make
fashion design more creative and imaginative based on our dataset. The dataset
will be released soon.Comment: 11 pages, 8 figure
Asymmetric quantum well broadband thyristor laser
A broadband thyristor laser based on InGaAs/GaAs asymmetric quantum well (AQW) is fabricated by metal organic chemical vapor deposition (MOCVD). The 3-μm-wide Fabry–Perot (FP) ridge-waveguide laser shows an S-shape I−V characteristic and exhibits a flat-topped broadband optical spectrum coverage of ~27 nm (Δ−10 dB) at a center wavelength of ~1090 nm with a total output power of 137 mW under pulsed operation. The AQW structure was carefully designed to establish multiple energy states within, in order to broaden the gain spectrum. An obvious blue shift emission, which is not generally acquired in QW laser diodes, is observed in the broadening process of the optical spectrum as the injection current increases. This blue shift spectrum broadening is considered to result from the prominent band-filling effect enhanced by the multiple energy states of the AQW structure, as well as the optical feedback effect contributed by the thyristor laser structure
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