Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>In this work, we study the kick dynamics of periodically driven quantum systems, and provide a time-independent effective Hamiltonian with the analytical form to reasonably describe the effective dynamics in a long timescale. It is shown that the effective coupling strength can be much larger than the coupling strength of the original system in some parameter regions, which stems from the zero time duration of kicks. Furthermore, different regimes can be transformed from and to each other in the same three-level system by only modulating the period of periodic kicks. In particular, the population of excited states can be selectively suppressed in periodic kicks, benefiting from the large detuning regime of the original system. Finally, some applications and physical implementation of periodic kicks are demonstrated in quantum systems. Those unique features would make periodic kicks becoming a powerful tool for quantum state engineering.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>This paper investigates information spreading from the perspective of topological phase transition. Firstly, a new hybrid network is constructed based on the small-world networks and scale-free networks. Secondly, the attention mechanism of online users in information spreading is studied from four aspects: social distance, individual influence, content richness, and individual activity, and a dynamic evolution model of “connecting with spreading” is designed. Eventually, numerical simulations are conducted in three types of networks to verify the validity of the proposed dynamic evolution model. The simulation results show that topological structure and node influences in different networks have undergone phase transition, which is consistent with the phenomenon that followers and individual influence in real social networks experience phase transition within a short period. The infection density of networks with the dynamic evolution rule changes faster and reaches higher values than that of networks without the dynamic evolution rule. Furthermore, the simulation results are compared with the real data, which shows that the infection density curve of the hybrid networks is closer to that of the real data than that of the small-world networks and scale-free networks, verifying the validity of the model proposed in this paper.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>An extended Su-Schrieffer-Heeger (SSH) model containing four periods of the hopping coefficients, called SSH4 model, is constructed to explore robust quantum state transfer. The gap state protected by the energy gap plays the role of the topological channel where the particle initially located at the last lattice site has the probability to arise at the first and all even lattice sites equally. Serving those sites as ports, a multi-port router can be realized naturally, and the fidelity reaches unity in a wide range of parameters under the long chain and random disorder. Further, when we reduce the third intracell hopping to a small value, the occupancy probability of the second lattice site in every unit cell will reduce to zero, by which a new topological router can be induced. In addition, our SSH4 model can work as a 1/3 beam splitter. Namely, the particle initially occupies the first lattice site and finally appears with equal probability at three lattice sites. And it also can realize a 1/2 beam splitter. Our four-period SSH model provides a novel way for topological quantum information processing and can engineer two kinds of quantum optical devices.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Adding additives into peroskite precursor solution has been proven as an simple and efficent strategy to improve the quality of peroskite films. In this work, we demonstrate an effective additive strategy to improve the quality of all-inorganic perovskite films by adding a novel silazane additive HDMS. The PCE of the opitimized devices enhanced from 14.55% to 15.31% with a <jats:italic>V</jats:italic> <jats:sub>OC</jats:sub> over 1.26 V due to the higher quality perovskite films with lower trap density after the incoporation of HDMS. More interestingly, the HDMS devices exhibit superior humidity and thermal stability compared with the control ones. This work provides a simple and efficient strategy to enhance the device performance and stability of all-inorganic perovskite solar cells, which could fercilitate its commercialization.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>After decades of theoretical studies, the rich phase states of active matter and cluster kinetic processes are still of research interest. And how to efficiently calculate the dynamical processes under their complex conditions becomes an open problem. Recently, machine learning methods have been proposed to predict the degree of coherence of active matter systems. In this way, the phase transition process of the system is quantified and studied. In this paper, we use Graph Network as a powerful model to determine the evolution of active matter with variable individual velocities solely based on the initial position and state of the particles. The Graph Network accurately predicts the order parameters of the system in different scale models with different individual velocities, noise and density to effectively evaluate the effect of diverse condition. Compared with the classical physical deduction method, we demonstrate that Graph Network prediction is excellent, which could save significantly computing resources and time. In addition to active matter, our method can be applied widely to other large-scale physical systems.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>A novel SiC double-trench MOSFET with integrated MOS-channel diode is proposed and investigated by Sentaurus TCAD simulation. The new SiC MOSFET has a trench gate and a stepped-trench source, and features an integrated MOS-channel diode on the top sidewall of the source Trench (MT MOS). In the reverse conduction state, the MOS-channel diode turns on firstly to prevent the internal parasitic body diode being activated, and thus reduces the turn-on voltage (<jats:italic>V</jats:italic> <jats:sub>F</jats:sub>) and suppresses the bipolar degradation phenomena. The <jats:italic>V</jats:italic> <jats:sub>F</jats:sub> of 1.70V (@ <jats:italic>I</jats:italic> <jats:sub>ds</jats:sub> = -100 A/cm<jats:sup>2</jats:sup>) for the SiC MT MOS is 38.2% lower than that of SiC double-trench MOSFET (DT MOS). Meanwhile, the reverse recovery charge <jats:italic>Q</jats:italic> <jats:sub>rr</jats:sub> of the MT MOS is 58.7% lower than that of the DT MOS at <jats:italic>I</jats:italic> <jats:sub>load</jats:sub> = 700A/cm<jats:sup>2</jats:sup>, and thus the reverse recovery loss is reduced. Furthermore, owing to the modulation effect induced by the double trenches, the MT MOS preserves same superior forward conduction and blocking performance as those of DT MOS, with 22.9% and 18.2% improvement on <jats:italic>BV</jats:italic> and <jats:italic>R</jats:italic> <jats:sub>ON,sp</jats:sub> than the trench gate MOSFET with planar integrated SBD (ST MOS).</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Elliptical Airy vortex beams (EAVBs) can spontaneously form easily identifiable topological charge focal spots. They are used for topological charge detection of vortex beams because they have the abruptly autofocusing properties of circular Airy vortex beams and exhibit unique propagation characteristics. In this paper, we study the use of the dynamic phase and Pancharatnam-Berry phase principles for the generation and modulation of EAVBs by designing complex-amplitude metasurface and phase-only metasurface, respectively, at an operating wavelength of 1500 nm. It is found that the focusing pattern of EAVBs in the autofocusing plane splits into |m|+1 tilted bright spots from the original ring, and the tilted direction is related to the sign of the topological charge number m. Due to the advantages of ultra-thin, ultra-light, and small size of the metasurface, our designed metasurface device has potential applications in improving the channel capacity based on orbital angular momentum communication, information coding, and particle capture compared to spatial light modulation systems that generate EAVBs.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Terahertz time-domain spectroscopy (THz-TDS) is an effective nondestructive and noninvasive tool for investigating sulfur-containing pigments. Combined with Raman spectroscopy and vibrational mode analysis, it is significant for artifact identification and conservation. In this paper, the terahertz absorption spectra of pararealgar (As<jats:sub>4</jats:sub>S<jats:sub>4</jats:sub>) and orpiment (As<jats:sub>2</jats:sub>S<jats:sub>3</jats:sub>) samples mixed with polytetrafluoroethylene (PTFE) were characterized in the range of 0.2 to 2.2 THz, and the distinctive peaks were perceived, respectively. Meanwhile, qualitative analysis was also implemented using Raman spectroscopy as a complementary technique. The lattice vibrations were deduced using solid-state density functional theory (ss-DFT) simulations, illustrating characteristic absorption peaks to be assigned to specific crystalline structures and dynamics diversely. This work provides reliable databases of sulfur-containing pigments by THz technology toward actual analysis and diagnosis of cultural relics.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Microstructural responses of In<jats:sub>0.32</jats:sub>Ga<jats:sub>0.68</jats:sub>N and In<jats:sub>0.9</jats:sub>Ga<jats:sub>0.1</jats:sub>N films to 2.25 GeV Xe ion irradiation have been investigated using X-ray diffraction, Raman scattering, ion channeling and transmission electron microscope. It is found that the In-rich In<jats:sub>0.9</jats:sub>Ga<jats:sub>0.1</jats:sub>N is more susceptible to irradiation than Ga-rich In<jats:sub>0.32</jats:sub>Ga<jats:sub>0.68</jats:sub>N. The Xe ion irradiation with a fluence of 7×10<jats:sup>11</jats:sup> ions/cm<jats:sup>2</jats:sup> leads to little damage in In<jats:sub>0.32</jats:sub>Ga<jats:sub>0.68</jats:sub>N, but an obvious lattice expansion in In<jats:sub>0.9</jats:sub>Ga<jats:sub>0.1</jats:sub>N. The level of lattice disorder in In<jats:sub>0.9</jats:sub>Ga<jats:sub>0.1</jats:sub>N increases after irradiation, which is due to the huge electronic energy deposition of the incident Xe ions. However, no Xe ion tracks are observed to be formed, which is attributed to the very high velocity of 2.25 GeV Xe ions. Point defects and/or small defect clusters are likely the dominating defect type in the Xe-irradiated In<jats:sub>0.9</jats:sub>Ga<jats:sub>0.1</jats:sub>N.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The space-confined synthesis method has been an efficient way for the preparation of linear carbon chains. However, the large-scale preparation of linear carbon chains still faces many challenges due to the lack of methods for the large-scale synthesis of precursors, such as short carbon chains (polyynes), and regulation technology for the transport of reactants in one-dimensional space. Here, we report a facile method for the rapid preparation of polyynes in large quantities using a commercial laser marking machine. Spectroscopic characterizations show that a large number of polyynes, such as C<jats:sub>8</jats:sub>H<jats:sub>2</jats:sub>, C<jats:sub>10</jats:sub>H<jats:sub>2</jats:sub>, C<jats:sub>12</jats:sub>H<jats:sub>2</jats:sub>, and C<jats:sub>14</jats:sub>H<jats:sub>2</jats:sub>, can be produced by ablating the graphite plate immersed in the organic liquid using a laser marking machine. The results of in situ Raman spectroscopy investigation of C<jats:sub>2n</jats:sub>H<jats:sub>2</jats:sub>-filled single-walled carbon nanotubes further confirm that a variety of polyyne molecules are synthesized. Meanwhile, in situ Raman spectroscopy also shows that the local heating treatment can accelerate the filling process of C<jats:sub>2n</jats:sub>H<jats:sub>2</jats:sub> into one-dimensional channels. This work provides new insights into the study of linear carbon chains and space-confined synthesis methods.</jats:p>