关键词：
Photonic spin Hall effect;Transverse beam shift;Tuning range;Insulating-metallic phase transition
摘要：
The photonic spin Hall effect (PSHE) can manifest as the spin-dependent splitting (perpendicular to the plane of incidence) of a light beam, i.e., transverse beam shift. Introducing dynamically tunable PSHE into post-fabricated systems has great potential for the new type of photonic devices and its tuning range can be manipulated with different reconfigurable methods. Most of these methods are based on modifying the refractive index of bulk or interface materials. However, the perturbation on the refractive index is usually small, leading to difficulty in enhancing PSHE. Fortunately, the changes in the refractive index of Vanadium Dioxide (VO2) with insulating-metallic phase transition can be larger in several orders than that of other materials, making it possible for enhancing PSHE to have greater tuning range. Here, to explore the dynamically tunable PSHE based on the insulating-metallic phase transition of VO2, the transverse beam shift (as an indicator of PSHE) was calculated with a full wave theory at a wavelength of 1550 nm in a layered structure. Without a gold layer, only the PSHE of the H-polarized beam shows significant tunability in the insulating-metallic phase transition of VO2. With the Au layer, the PSHE of the H- and V-polarized beam is enhanced around the Brewster and Brewster-like (originating from the destructive interference between the nanosized layers) angle, respectively. For H- and V-polarized beams, the tuning range of PSHE is mainly determined by the insulating phase of VO2 and can be enhanced with the Au layer. Finally, as an example, the enhanced tuning range makes the output of a two-digit binary code conversion based on PSHE easier to recognize. These results offer us possible ways to control the tuning range of PSHE in post-fabricated systems and provide more potential for new applications.
摘要：
The massive collection and transmission of various crop and livestock data in smart agriculture leads to serious security concerns. Furthermore, many Internet of Things (IoT) devices in smart agriculture are battery-powered, with limited energy resources. Therefore, a low energy lightweight block cipher (LELBC) is proposed to overcome the data leakage problem during sensor data transmission in smart agriculture. Firstly, a new permutation substitution permuta-tion (PSP) structure is proposed, taking into account the energy resource constraints of unified encryption and decryption (ED) circuits. It has highly consistent encryption and decryption and a good diffusion effect. Secondly, a 4-bit low energy involutive S-box is obtained based on a genetic algorithm. The proposed S-box has lower area and latency compared to the existing S-boxes. The experimental data show that LELBC consumes 1864 gate equivalents (GE) in area and 6.99 mu J/bit in energy (encryption + decryption) under the UMC 0.18 mu m 1P6M process library. LELBC decreases energy and area consumption by 24.02% and 24.04%, respectively, compared to Midori. Finally, a temperature collection and encryption transmission platform is established. LELBC is deployed on the platform to encrypt the collected data, establishing the first line of defense for the secure transmission of smart agriculture sensor data.
通讯机构：
[Tang, ZK ] U;Univ Hunan Prov, Key Lab Micronano Energy Mat & Applicat Technol, Hengyang 421002, Peoples R China.
摘要：
Two-dimensional material-supported single metal atom catalysts have been extensively studied and proved effective in electrocatalytic reactions in recent years. In this work, we systematically investigate the OER catalytic properties of single metal atoms supported by the NiN(2) monolayer. Several typical transition metals with high single atom catalytic activity, such as Fe, Co, Ru, Rh, Pd, Ir, and Pt, were selected as catalytic active sites. The energy calculations show that transition metal atoms (Fe, Co, Ru, Rh, Pd, Ir, and Pt) are easily embedded in the NiN(2) monolayer with Ni vacancies due to the negative binding energy. The calculated OER overpotentials of Fe, Co, Ru, Rh, Pd, Ir and Pt embedded NiN(2) monolayers are 0.92 V, 0.47 V, 1.13 V, 0.66 V, 1.25 V, 0.28 V, and 0.94 V, respectively. Compared to the 0.57 V OER overpotential of typical OER noble metal catalysts IrO(2), Co@NiN(2) and Ir@NiN(2) exhibit high OER catalytic activity due to lower overpotential, especially for Ir@NiN(2). The high catalytic activity of the Ir embedded NiN(2) monolayer can be explained well by the d-band center model. It is found that the adsorption strength of the embedded TM atoms with intermediates follows a linear relationship with their d-band centers. Besides, the overpotential of the Ir embedded NiN(2) monolayer can be further reduced to 0.24 V under -2% biaxial strain. Such findings are expected to be employed in more two-dimensional material-supported single metal atom catalyzed reactions.
作者机构：
[Yao, Yong-Sheng; Wei, Xiao-Lin; Gong, Ze-Ting; Tang, Zhen-Kun; Li, Jun-Yao; Liu, Yao-Zhong; Liang, Zheng; Tang, ZK] Hengyang Normal Univ, Univ Hunan Prov, Key Lab Micronano Energy Mat & Applicat Technol, Hengyang 421002, Peoples R China.;Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang, Peoples R China.
通讯机构：
[Wei, XL ; Tang, ZK] H;Hengyang Normal Univ, Univ Hunan Prov, Key Lab Micronano Energy Mat & Applicat Technol, Hengyang 421002, Peoples R China.
摘要：
The need for low-carbon solar electricity production has become increasingly urgent for energy security and climate change mitigation. However, the bandgap and carrier separation critical requirements of high-efficiency solar cells are difficult to satisfy simultaneously in a single material. In this work, several van der Waals ZnIn(2)X(4) (X = S, Se, and Te) heterostructures were designed based on density functional theory. Our results suggest that both ZnIn(2)S(4)/ZnIn(2)Se(4) and ZnIn(2)Se(4)/ZnIn(2)Te(4) heterostructures are direct bandgap semiconductors at the Γ point. Besides, obvious carrier spatial separations were observed in the ZnIn(2)S(4)/ZnIn(2)Se(4) and ZnIn(2)Se(4)/ZnIn(2)Te(4) heterostructures. Interestingly, the ZnIn(2)S(4)/ZnIn(2)Se(4) heterostructure has a suitable bandgap of 1.43 eV with good optical absorption in the visible light range. The calculated maximum theoretical photoelectric conversion efficiency of ZnIn(2)S(4)/ZnIn(2)Se(4) heterostructure was 32.1%, and it can be further enhanced to 32.9% under 2% tensile strain. Compared to single-layer ZnIn(2)X(4) materials, the electron effective mass of the ZnIn(2)S(4)/ZnIn(2)Se(4) heterostructure is relatively low, which results in high electron mobility in the heterostructure. The suitable bandgap, obvious carrier separation, high electron mobility, and excellent theoretical photoelectric conversion efficiency of the ZnIn(2)S(4)/ZnIn(2)Se(4) heterostructure make it a promising candidate for novel 2D-based photoelectronic devices and solar cells.
期刊：
Physica E-Low-Dimensional Systems & Nanostructures,2024年159:115912 ISSN：1386-9477
通讯作者：
Zhaosen Liu<&wdkj&>Hou Ian
作者机构：
[Zhaosen Liu] College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang 421002, China;[Hou Ian] Institute of Applied Physics and Materials Engineering, University of Macau, Macao Special Administrative Region of China
通讯机构：
[Zhaosen Liu] C;[Hou Ian] I;Institute of Applied Physics and Materials Engineering, University of Macau, Macao Special Administrative Region of China<&wdkj&>College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang 421002, China
摘要：
Magnetic skyrmions can be generated, destroyed and driven to motion by electric spin currents in metals based on the spin transfer torque (STT) mechanism. However, the STT technique does not work in insulating materials because no electric currents can pass through. Fortunately, the magnetoelectric (ME) interaction that is present in multiferroic insulators makes it possible to manipulate magnetic skyrmions by applying electric fields. We have recently simulated ferroelectric (FE) skyrmionic crystals (or skyrmionic lattices so that skyrmionic crystals can be abbreviated as SkLs) formed in two-dimensional (2D) ferromagnetic (FM) multiferroic materials. Antiferromagnets are more abundant in nature. For this reason, we employ here a quantum computational method which we have developed in recent years to investigate the magnetic and polarized electric dipole textures of a 2D antiferromagnetic (AM) multiferroic system. Consequently, we observe in simulations that antiferroelectric (AE) and AM skyrmionic crystals can be generated simultaneously in a broad temperature and magnetic field phase region. Each of these AM and AE SkLs can be decomposed into two ferromagnetic or ferroelectric lattices which are FM or FE SkLs respectively, an FE skyrmion in one FE SkL is an electric dipole complex formed around the interstitial site of another FE SkL. The topological charges of the FE skyrmions are quantized to be integers, half integers or the odd multiples of ±0.25 especially within subsequently normally applied electric fields. In a strong external magnetic field, AE SkL and AM vortical crystal (VL) usually coexist. A subsequently applied perpendicular electric field is able to stabilize or destroy the both sorts of SkLs, and considerably elevate the coexisting temperatures of the AE SkL and AM VL textures even the electric field is very weak.
摘要：
Developing high-efficiency electrocatalysts for the oxygen evolution reaction (OER) remains a crucial bottleneck on the way to the water splitting for producing clean fuel (H2). Compared with single atom catalysis (SACs), dualatom catalysts (DACs) have attracted great interest due to higher OER catalytic efficiency. In this work, the OER properties of dual-metal-N4 embedding armchair single-walled carbon nanotubes (D-MN4/CNTs) were systematic studied by density functional theory (DFT) simulations. Our results indicate that CoN4 embedding armchair CNTs exhibit higher OER activity than the corresponding planar structure, especially for CoN4 embedding in armchair CNT (4, 4) (CNT4). For MN4-CoN4 co-embedding CNTs, the TiN4-CoN4/CNTs have good OER synergistic effect with the lowest overpotential. Besides, the diameter of CNTs have a significant impact on the OER efficiency. The lowest reaction overpotential 0.47 V were obtained in TiN4-CoN4/CNT4 with a 5.69 angstrom tube diameter. Interestingly, compressive stress will further enhance the synergistic effect between two metal atoms in the OER reaction. The OER overpotential of CoN4-TiN4 embedding armchair CNT4 can reduce to 0.40 V under the -4 % uniaxial compression strain. These works were expected to better understand the synergistic mechanisms and design high-efficiency dual-atom OER electrocatalysts.
作者机构：
[Wang, Peng; Fan, Chao; Zhu, Meiyi; He, Haiping; Dai, Xingliang; Ye, Zhizhen] School of Materials Science and Engineering, State Key Laboratory of Silicon and Advanced Semiconductor Materials, Zhejiang University, Hangzhou 310027, People's Republic of China;[Wang, Peng; Fan, Chao; Zhu, Meiyi; He, Haiping; Dai, Xingliang; Ye, Zhizhen] Wenzhou Key Laboratory of Novel Optoelectronic and Nano Materials, Zhejiang Provincial Engineering Research Center of Oxide Semiconductors for Environmental and Optoelectronic Applications, Institute of Wenzhou, Zhejiang University, Wenzhou 325006, People's Republic of China;[Fan, Chao; Zhu, Meiyi; He, Haiping; Dai, Xingliang; Ye, Zhizhen] Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, Taiyuan, Shanxi 030000 People's Republic of China;[Xu, Xing] College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang 421010, People's Republic of China;[Zhang, Qinglin] School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
摘要：
Semiconductor planar nanowire arrays (PNAs) are essential for achieving large-scale device integration. Direct heteroepitaxy of PNAs on a flat substrate is constrained by the mismatch in crystalline symmetry and lattice parameters between the substrate and epitaxial nanowires. This study presents a novel approach termed "self-competitive growth" for heteroepitaxy of CsPbBr(3) PNAs on mica. The key to inducing the self-competitive growth of CsPbBr(3) PNAs on mica involves restricting the nucleation of CsPbBr(3) nanowires in a high-adsorption region, which is accomplished by overlaying graphite sheets on the mica surface. Theoretical calculations and experimental results demonstrate that CsPbBr(3) nanowires oriented perpendicular to the boundary of the high-adsorption area exhibit greater competitiveness in intercepting the growth of nanowires in the other two directions, resulting in PNAs with a consistent orientation. Moreover, these PNAs exhibit low-threshold and stable amplified spontaneous emission under one-, two-, and three-photon excitation, indicating their potential for an integrated laser array.
作者机构：
[Jie Li; Zhen-Jun Yang] College of Physics, Hebei Key Laboratory of Photophysics Research and Application, Hebei Normal University, Shijiazhuang 050024, China;[Zhi-Ping Dai] College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang 421002, China
通讯机构：
[Zhen-Jun Yang] C;College of Physics, Hebei Key Laboratory of Photophysics Research and Application, Hebei Normal University, Shijiazhuang 050024, China
摘要：
In this paper, the evolution characteristics of periodic transmission of circularly symmetric multi-ring solitons in optical nonlocal materials based on nonlinear Schrödinger equation are investigated in detail. The transmission expression of circularly symmetric multi-ring solitons has been derived. It was found that the number and size of rings in these solitons can be controlled by initial parameters. The transmission of circularly symmetric multi-ring solitons is similar to that of high-order temporal solitons in nonlinear fibers, exhibiting periodic variations. When the input energy is a specific value, the statistical width of circularly symmetric multi-ring solitons remains constant during transmission, otherwise it exhibits periodic changes, which can be considered as generalized breathing solitons. The influence of various parameters on the transmission characteristics has been analyzed in detail, and some important transmission characteristics have been intuitively demonstrated through numerical simulation.
摘要：
Soil surface carbon dioxide (CO2) fluxes hold significant implications for comprehending carbon cycling, global climate change, and ecosystem functioning. Accurate understanding and quantification of this flux are crucial for assessing the carbon dynamics of ecosystems and predicting the impacts of climate change. In this study, we analyzed the variation pattern of CO2 concentration within the accumulated chamber from Fick's law, accounting for diffusion gradient effect and considering leakage effect. We developed a simple model to measure the soil surface CO2 flux, and used the model to calculate the values of CO2 fluxes on a specific soil surface. Comparing the fitting results of the proposed nonlinear model with traditional linear models for the measurement data, we found that the linear model underestimated by at least 18%, even up to 45%. Overall, our research indicates that the proposed model exhibits significant advancement and higher predictive reliability, successfully evaluating soil surface CO2 flux.
摘要：
Cr3+ doped phosphors with deep -red luminescence hold great promise as artificial lighting sources for plants growth. Among them, alpha-Al2O3:Cr3+ is featured with an ultra -intense pure zero phonon line (ZPL) emission with negligible sidebands. Nonetheless, further enhancements in its luminescence thermal stability are required to fully unlock its potential for practical applications. To tackle this challenge, we propose that Al20B4O36 with a negative expansion coefficient could serve as a more favorable host materials for Cr3+ ion, thereby enhancing the luminescence thermal stability. Our first -principles calculations have unveiled similar electronic structures for alpha-Al2O3:Cr3+ and Al20B4O36:Cr3+, suggesting that the observed zero phonon R -line (2Eg) emission, arising from the 2Eg -> 4A2g transition in alpha-Al2O3:Cr3+, might also be present in Al20B4O36:Cr3+. Based on these findings, we prepared Al20B4O36:Cr3+ phosphors using a simple solid reaction method and confirmed that Al20B4O36:Cr3+ indeed exhibits a similar ultra -intense pure ZPL emission centered at 694 nm. Moreover, Al20B4O36:Cr3+ phosphors demonstrate remarkable properties including a high internal quantum efficiency (IQE) of 98.2 % and superior luminescence thermal stability compared to alpha-Al2O3:Cr3+. A phosphor converted light emitting diode (pc -LED) is developed by coating Al20B4O36:Cr3+ phosphor onto a near -ultraviolet LED chip. The lighting from this deep -red LED significantly impacts the photomorphogenesis of bean sprouts. Our study showcases a rational approach to design novel Cr3+ doped phosphors with enhanced luminescent properties, tailored for specific applications.
期刊：
Results in Physics,2024年57:107442 ISSN：2211-3797
通讯作者：
Zhen-Jun Yang
作者机构：
[Zhi-Ping Dai; Peng Pan] College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang 421002, China;[Jia-Qi Liu; Zhao-Guang Pang; Zhen-Jun Yang] College of Physics, Hebei Key Laboratory of Photophysics Research and Application, Hebei Normal University, Shijiazhuang 050024, China
通讯机构：
[Zhen-Jun Yang] C;College of Physics, Hebei Key Laboratory of Photophysics Research and Application, Hebei Normal University, Shijiazhuang 050024, China
摘要：
The transmission characteristics of circular–linear edge dislocation vortex (CLEDV) beams in optical nonlocal medium is investigated analytically and numerically in detail. The analytical expression for the transmission of CLEDV beams is derived, and the transmission characteristics of CLEDV beams are illustrated in figures. The influence of various parameters of CLEDV beams on transmission characteristics is discussed, including statistical spot size, input power, topological charge, etc. The results indicate that the main transverse intensity of CLEDV beams can maintain a crescent shaped distribution and rotate periodically under the influence of topological charges. For different input powers, the variations of the statistical spot size of CLEDV beams in two transverse directions exhibit diverse behaviors: they can be diametrically opposite, simultaneously expand or compress, remain constant in one direction while periodically changing in the other. This complexity highlights the intricate dynamics of CLEDV beams in optical nonlocal medium.
摘要：
Forming ohmic contacts between metals and semiconductors is critical to achieving high-performance and energy-efficient electronics. Here we investigate the interface properties of WSi2N4 contacted by Mo2B, O-modified Mo2B (Mo2BO2) and OH-modified Mo2B (Mo2B(OH)(2)) nanosheets using density functional theory simulations. We show that WSi2N4 and Mo2B form n-type Schottky contacts with barrier heights that are robust against external electric fields. In contrast, functionalizing Mo2B with O and OH causes the work function to energetically down- and up-shift significantly, thus forming both n-type and p-type ohmic contacts with WSi2N4, respectively. The possibility of achieving both p-type and n-type ohmic contacts immediately suggests the role of surface-engineered Mo2B as a key enabler towards WSi2N4-based complementary metal-oxide-semiconductor (CMOS) device technology in which both n-type and p-type devices are needed. We further demonstrate the emergence of quasi-ohmic contact with ultralow lateral Schottky barrier and zero vertical interfacial tunneling barriers in Mo2B(OH)(2)-contacted WSi2N4 - a feature rarely found in other 2D/2D metal/semiconductor contacts, thus demonstrating surface-engineered Mo2B as a promising electrode to WSi(2)N(4 )with high charge injection efficiency. These results offer design insights useful for the development of high-performance 2D semiconductor CMOS device technology.
期刊：
Journal of Instrumentation,2024年19(02):T02017 ISSN：1748-0221
作者机构：
[Shuai Yuan; Ruomei Xie; Shuaibin Liu; Huiying Li; Haibo Yi; Jiale Sun; Zhipeng Liu; Jiulin Wu; Fen Lin; Tao Hu; Yixiang Mo; Hongzhi Yuan; Yanliang Tan] College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang, Hunan Province 421008, China
摘要：
Radon and its decay products emit internal radiation in the respiratory system upon inhalation, which is a significant contributor to the development of lung cancer in humans. Accurate measurement of radon concentration is undoubtedly very important. Among the commonly used radon measurement methods, the electrostatic collection method stands out. This method involves counting the energy spectrum peaks of alpha particles, generated by the decay of radon daughters Po-218 and Po-214, which are collected on the surface of a semiconductor detector to determine radon concentration. According to experimental findings, measurements at different ambient temperatures cause Po-218 and Po-214 to peak drift. This drift adversely affects the accuracy of radon measurement using traditional methods. This study focuses on the characteristics of α-energy spectra from Po-218 and Po-214. It calculates the peak heights for all α-energy spectra and identifies the two peaks with the highest heights. Subsequently, an algorithm is developed to automatically track the peak positions of Po-218 and Po-214, accurately locating their counting intervals. The results demonstrate that the algorithm successfully achieves the desired outcomes through experiments conducted at different temperatures and measurement durations, thus validating its effectiveness. This method holds significant practical value in ensuring the accuracy of radon measurement.
期刊：
Journal of Colloid and Interface Science,2024年664:128-135 ISSN：0021-9797
通讯作者：
Yang, Liwen
作者机构：
[Liang, Yongle; Zhang, Huaijun; Yang, Hengyu; Niu, Fengjun] School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China;[Xu, Guobao] School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China;[Wei, Xiaolin] College of Physics and Electronics Engineering, Hengyang Normal University, Hengyang 421002, China;[Yang, Liwen] School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China. Electronic address: ylwxtu@xtu.edu.cn
通讯机构：
[Yang, Liwen] S;School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China. Electronic address:
关键词：
Aqueous zinc ion batteries;Electrolyte;Interface engineering;Rare earth ions;Zinc anode
摘要：
Aqueous zinc-ion batteries (AZIBs) have become an ideal candidate for large-scale energy storage systems owing to their inherent safety and highly competitive capacity. However, severe dendrite growth and side reactions on the surface of zinc metal anodes lead to quick performance deterioration, seriously impeding the commercialization of AZIBs. In this work, a self-regulated zinc metal/electrolyte interface is constructed to solve these problems by incorporating the trivalent Gd(3+) additive with a lower effective reduction potential into the aqueous ZnSO(4) electrolyte. It is revealed that the inert Gd(3+) ions preferentially adsorb on the active sites of the zinc anode, and the induced electrostatic shielding layer is beneficial to uniform Zn deposition. Meanwhile, the adsorbed Gd(3+) ions act as a buffer interface to lower the direct contact of the zinc anode with water molecules, thereby suppressing the interfacial parasitic reaction. These features endow the Zn//Zn battery using 0.2M Gd(3+) ions with 2940h of cycling life at 5mAcm(-2) and a cumulative plating capacity (CPC) of 6.2 Ah cm(-2) at 40mAcm(-2). When assembling with a MnO(2) cathode, the full cell using the modified electrolyte exhibits a high capacity of 268.9 mAh/g at 0.2 A/g, as well as improved rate capability and cycle stability. The results suggest the great potential of a rare earth ion additive in reinforcing Zn metal anodes for developing practical AZIBs.
摘要：
Understanding how the electronic state of transition metal atoms can influence molecular adsorption on a substrate is of great importance for many applications. Choosing NH(3) as a model molecule, its adsorption behavior on defected SnS(2) monolayers is investigated. The number of valence electrons n is controlled by decorating the monolayer with different transition metal atoms, ranging from Sc to Zn. Density-Functional Theory based calculations show that the adsorption energy of NH(3) molecules oscillates with n and shows a clear odd-even pattern. There is also a mirror symmetry of the adsorption energies for large and low electron numbers. This unique behavior is mainly governed by the oxidation state of the TM ions. We trace back the observed trends of the adsorption energy to the orbital symmetries and ligand effects which affect the interaction between the 3σ orbitals (NH(3)) and the 3d orbitals of the transition metals. This result unravels the role which the spin state of TM ions plays in different crystal fields for the adsorption behavior of molecules. This new understanding of the role of the electronic structure on molecular adsorption can be useful for the design of high efficiency nanodevices in areas such as sensing and photocatalysis.
通讯机构：
[Zhang, DZ ] H;[Ma, J ] C;Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421008, Peoples R China.;Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China.
摘要：
The plasma equilibrium plays a crucial role in nuclear fusion studies, serving as the foundation for various aspects of fusion research, including plasma stability, transport, and current drive. In this paper, a new Grad-Shafranov equation solver is developed for the fixed-boundary plasma equilibria with toroidal flow. This solver utilizes the pressure profile, safety factor profile (not current profile), and any two profiles of the toroidal angular velocity, plasma temperature, and square of the Mach number as inputs. The numerical results obtained by this solver exhibit good agreement with known analytic solution under identical parameters, and the potential applications of the solver are demonstrated through several numerical equilibria with toroidal flow. It is very convenient to apply this code to simulate the tokamak equilibrium with a smooth plasma shape. In addition, the effect of toroidal flow on the plasma equilibria is investigated as a simple application. The results reveal a notable outward shift in the contour profiles of magnetic flux surface, density, pressure, and temperature induced by toroidal flow.
期刊：
Journal of Physical Chemistry Letters,2024年15(10):2867-2875 ISSN：1948-7185
作者机构：
[Tan, Jieyao; Jiang, Xingxing] College of Physics and Electronics Engineering, Hengyang Normal University, Hengyang 421002, China;[Liu, Dongyu; Vasenko, Andrey S; Jiang, Xingxing] HSE University, 101000 Moscow, Russia;[Feng, Yexin; Chen, Ke-Qiu] Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, China;[Long, Run] Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China;[Vasenko, Andrey S] Donostia International Physics Center (DIPC), 20018 San Sebastián-Donostia, Euskadi, Spain
摘要：
The rapid recombination of photogenerated carriers heavily restricts the photocatalytic efficiency. Here, we propose a new strategy to improve catalytic efficiency based on the ferroelectric van der Waals heterostructure (CuBiP(2)Se(6)/C(2)N). Combining density functional theory and the nonadiabatic molecular dynamics (NAMD) method, we have systematically analyzed the ground-state properties and carrier dynamics images in the CuBiP(2)Se(6)/C(2)N heterostructure. Our calculations showed that the ferroelectric polarization of CuBiP(2)Se(6) provides the internal driving force for the photogenerated carriers separation. NAMD results demonstrate that the excited-state carrier transfer and recombination processes in the CuBiP(2)Se(6)/C(2)N are consistent with a type II mechanism. Meanwhile, constructing the ferroelectric heterostructure can effectively prolong the carrier lifetime, from ∼65.98 to ∼124.54 ps. Moreover, the high quantum efficiency and tunable band edge positions mean that the CuBiP(2)Se(6)/C(2)N heterostructure is an excellent potential candidate material for photocatalytic water splitting.
期刊：
Scripta Materialia,2024年242:115958 ISSN：1359-6462
通讯作者：
Huang, SJ;Wei, XL
作者机构：
[Huang, Shouji] Shaoyang Univ, Dept Phys, Shaoyang 422000, Peoples R China.;[Yang, Liwen] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Peoples R China.;[Wei, Xiaolin] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.;[Xu, Guobao] Xiangtan Univ, Sch Mat Sci & Engn, Xiangtan 411105, Hunan, Peoples R China.
通讯机构：
[Huang, SJ ] S;[Wei, XL ] H;Shaoyang Univ, Dept Phys, Shaoyang 422000, Peoples R China.;Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.
关键词：
MnO quantum dots;Anode;Carbon aggregates;Li ion batteries
摘要：
We develop a facile strategy to construct massive MnO quantum dots of average size 3 nm embedded in quasispherical N-doped carbon aggregates as anodes for Li ion batteries (LIBs). The unique nanostructure supplies an elastic conductive carbon frame to alleviate volume expansion, ensures almost the entire surface of each MnO particle participate in electrochemical reactions, shortens ion diffusion length, and enhances electronic conductivity. Moreover, ex-situ TEM and HRTEM findings prove excellent reversibility and stability. Therefore, nanocomposite anode shows outstanding characteristics, including a high reversible capacity with 1052 mAh g- 1 at 0.3 A g-1 after 160 cycles, excellent rate capability with 407 mAh g-1 at 5 A g -1, and a prolonged cycling lifespan of 677 mAh g-1 at 2.0 A g-1 after 550 cycles with capacity retention of 113 %. In addition, Li full cell also show outstanding electrochemical performances by using LiFePO4 as cathode, and employing a nanocomposite as the anode.
摘要：
Recently, both quartic self-similar pulses (QSSPs) and dissipative pure-quartic-solitons (DPQSs) pulses have been theoretically demonstrated in mode-locked fiber laser with pure positive fourth-order dispersion (FOD). Here, we investigate the existence regions and dynamics of those two soliton pulses by numerically solving the cubic-quintic Ginzburg-Landau equation. We find the positive FOD fiber laser tends to emit QSSPs in the presence of high nonlinear gain, while it is apt to generate DPQS pulses in the case of low nonlinear gain. An unstable pulse region separates the QSSP region from the DPQS region. The characteristics of QSSP and DPQS pulses are dependent on the nonlinear gain and FOD. The QSSP can carry more energy than that of DPQS pulse, because the DPQS pulse with large energy could be unstable due to the excessive pulse pedestal. Our results are not only useful for understanding the dynamics of the DPQS pulse and QSSP in the cubic-quintic Ginzburg-Landau equation with pure FOD, but also provide a guideline for generating high-energy pulses from the positive FOD fiber laser.
