Catálogo de publicaciones - revistas

<jats:p>Cd<jats:sub>3</jats:sub>As<jats:sub>2</jats:sub>, as a three-dimensional (3D) topological Dirac semimetal, has attracted wide attention due to its unique physical properties originating from the 3D massless Dirac fermions. While many efforts have been devoted to the exploration of novel physical phenomena such as chiral anomaly and phase transitions by using bulk crystals, the development of high-quality and large-scale thin films becomes necessary for practical electronic and optical applications. Here, we report our recent progress in developing single-crystalline thin films with improved quality and their optical devices including Cd<jats:sub>3</jats:sub>As<jats:sub>2</jats:sub>-based heterojunctions and ultrafast optical switches. We find that a post-annealing process can significantly enhance the crystallinity of Cd<jats:sub>3</jats:sub>As<jats:sub>2</jats:sub> in both intrinsic and Zn-doped thin films. With excellent characteristics of high mobility and linear band dispersion, Cd<jats:sub>3</jats:sub>As<jats:sub>2</jats:sub> exhibits a good optical response in the visible-to-mid-infrared range due to an advantageous optical absorption, which is reminiscent of 3D graphene. It also behaves as an excellent saturable absorber in the mid-infrared regime. Through the delicate doping process in this material system, it may further open up the long-sought parameter space crucial for the development of compact and high-performance mid-infrared ultrafast sources.</jats:p>

<jats:p>Two-dimensional (2D) magnetic crystals have attracted great attention due to their emerging new physical phenomena. They provide ideal platforms to study the fundamental physics of magnetism in low dimensions. In this research, magnetic tunneling junctions (MTJs) based on <jats:italic>X</jats:italic>Se<jats:sub>2</jats:sub> (<jats:italic>X</jats:italic>=Mn, V) with room-temperature ferromagnetism were studied using first-principles calculations. A large tunneling magnetoresistance (TMR) of 725.07% was obtained in the MTJs based on monolayer MnSe<jats:sub>2</jats:sub>. Several schemes were proposed to improve the TMR of these devices. Moreover, the results of our non-equilibrium transport calculations showed that the large TMR was maintained in these devices under a finite bias. The transmission spectrum was analyzed according to the orbital components and the electronic structure of the monolayer <jats:italic>X</jats:italic>Se<jats:sub>2</jats:sub> (<jats:italic>X</jats:italic>=Mn, V). The results in this paper demonstrated that the MTJs based on a 2D ferromagnet with room-temperature ferromagnetism exhibited reliable performance. Therefore, such devices show the possibility for potential applications in spintronics.</jats:p>

<jats:p>Si <jats:inline-formula> <jats:tex-math><?CDATA ${{\rm{p}}}^{+}{\rm{n}}$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">p</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> <mml:mi mathvariant="normal">n</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpb_28_10_107801_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> junction diodes operating in the mode of avalanche breakdown are capable of emitting light in the visible range of 400–900 nm. In this study, to realize the switching speed in the GHz range, we present a transient model to shorten the carrier lifetime in the high electric field region by accumulating carriers in both p and n type regions. We also verify the optoelectronic characteristics by disclosing the related physical mechanisms behind the light emission phenomena. The emission of visible light by a monolithically integrated Si diode under the reverse bias is also discussed. The light is emitted as spatial sources by the defects located at the p–n junction of the reverse-biased diode. The influence of the defects on the electrical behavior is manifested as a current-dependent electroluminescence.</jats:p>

<jats:p>We study the absorption of hydrogen of metal by the permeability method. With the help of the gas reaction controller (GRC), the absorptive capacity of hydrogen, which is a function of time, temperature and pressure, can be recorded. The effect of the performance of the hydrogen permeability of AlN coating on the titanium alloy surface structure is studied. In the research, the AlN is selected to be added to the titanium alloy sample VT6, and the properties of the titanium alloy are investigated, and the hydrogen absorption rate of the coating is calculated by performing the hydrogen saturation of the test sample. The results show that under 600 °C the AlN film reduces the hydrogen absorption rate of titanium alloy and improves the surface properties of VT6 alloy.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>It is widely accepted that the variation of ambient temperature has great influence on the battery model parameters and state-of-charge (SOC) estimation, and the accurate SOC estimation is a significant issue for developing the battery management system in electric vehicles. To address this problem, in this paper we propose an enhanced equivalent circuit model (ECM) considering the influence of different ambient temperatures on the open-circuit voltage for a lithium–ion battery. Based on this model, the exponential-function fitting method is adopted to identify the battery parameters according to the test data collected from the experimental platform. And then, the extended Kalman filter (EKF) algorithm is employed to estimate the battery SOC of this battery ECM. The performance of the proposed ECM is verified by using the test profiles of hybrid pulse power characterization (HPPC) and the standard US06 driving cycles (US06) at various ambient temperatures, and by comparing with the common ECM with a second-order resistance capacitor. The simulation and experimental results show that the enhanced battery ECM can improve the battery SOC estimation accuracy under different operating conditions.</jats:p>

<jats:p>A tunnel field-effect transistor (TFET) is proposed by combining various advantages together, such as non-uniform gate–oxide layer, hetero-gate-dielectric (HGD), and dual-material control-gate (DMCG) technology. The effects of the length of non-uniform gate–oxide layer and dual-material control-gate on the on-state, off-state, and ambipolar currents are investigated. In addition, radio-frequency performance is studied in terms of gain bandwidth product, cut-off frequency, transit time, and transconductance frequency product. Moreover, the length of non-uniform gate–oxide layer and dual-material control-gate are optimized to improve the on-off current ratio and radio-frequency performances as well as the suppression of ambipolar current. All results demonstrate that the proposed device not only suppresses ambipolar current but also improves radio-frequency performance compared with the conventional DMCG TFET, which makes the proposed device a better application prospect in the advanced integrated circuits.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We study opto-electromechanically induced transparency in a hybrid opto-electromechanical system made up of an optical cavity tunneling-coupled to an opto-mechanical cavity, which is capacitively coupled to a charged mechanical oscillator by a charged and moveable mechanical cavity mirror as an interface. By studying the effects of the different parameters on the output field, we propose a scheme to modulate the opto-electromechanically induced transparency (OEMIT). Our results show that the OEMIT with the transparency windows from single to double to triple can be modulated by changing the tunneling, opto-mechanical and electrical couplings. In addition, the explanation of the OEMIT with multi-windows is given by the energy level diagram based on quantum interference. Our investigation will provide an optimal platform to manipulate the transmission of optical field via microfabricated opto-electromechanical device.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The spin-dependent electronic transport properties of a zigzag zinc oxide (ZnO) nanoribbon are studied by using density functional theory with non-equilibrium Green’s functions. We calculate the spin-polarized band structure, projected density of states, Bloch states, and transmission spectrum of the ZnO nanoribbon. It is determined that all Bloch states are located at the edge of the ZnO nanoribbon. The spin-up transmission eigenchannels are contributed from Zn 4s orbital, whereas the spin-down transmission eigenchannels are contributed from Zn 4s and O 2p orbitals. By analyzing the current–voltage curves for the opposite spins of the ZnO nanoribbon device, negative differential resistance (NDR) and spin filter effect are observed. Moreover, by constructing the ZnO nanoribbon modified by the Zn-edge defect, the spin-up current is severely suppressed because of the destruction of the spin-up transmission eigenchannels. However, the spin-down current is preserved, thus resulting in the perfect spin filter effect. Our results indicate that the ZnO nanoribbon modulated by the edge defect is a practical design for a spin filter.</jats:p>

<jats:p>Cancer cell motility and its heterogeneity play an important role in metastasis, which is responsible for death of 90% of cancer patients. Here, in combination with a microfluidic technique, single-cell tracking, and systematic motility analysis, we present a rapid and quantitative approach to judge the motility heterogeneity of breast cancer cells MDA-MB-231 and MCF-7 in a well-defined three-dimensional (3D) microenvironment with controllable conditions. Following this approach, identification of highly mobile active cells in a medium with epithelial growth factor will provide a practical tool for cell invasion and metastasis investigation of multiple cancer cell types, including primary cells. Further, this approach could potentially become a speedy (∼hours) and efficient tool for basic and clinical diagnosis.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>It has come to the attention of the Editors of <jats:italic>Chinese Physics</jats:italic> B that the article entitled 'Ultrafast mode-locked fiber laser with zirconium disulfide on D-shaped fiber' should not have been accepted for publication because of its substantial replication of an article submitted to <jats:italic>Infrared Physics &amp; Technology</jats:italic>. Consequently, this paper has been withdrawn from publication.</jats:p>