Search

Due to high ion conductivity, low cost, and adjustable composition, antiperovskite has attracted much attention as a potentially useful material in solid-state batteries. Compared with simple antiperovskite, Ruddlesden–Popper (R–P) antiperovskite is an updated material, which is not only more stable but also reported to significantly enhance conductivity when added to simple antiperovskite. However, systematic theoretical research on R–P antiperovskite is scarce, hindering its further development. In this study, the recently reported easily synthesized R–P antiperovskite LiBr(Li2OHBr)2 is calculated for the first time. Comparative calculations were conducted on the transport performance, thermodynamic properties, and mechanical properties of H-rich LiBr(Li2OHBr)2 and H-free LiBr(Li3OBr)2. Our results indicate that due to the presence of protons, LiBr(Li2OHBr)2 is more prone to defects, and synthesizing more LiBr Schottky defects can improve its Li-ion conductivity. Young's modulus of the LiBr(Li2OHBr)2 is as low as 30.61 GPa, which is beneficial for its application as a sintering aid. However, the calculated Pugh's ratio (B/G) of 1.28 and 1.50, respectively, indicates that R–P antiperovskites LiBr(Li2OHBr)2 and LiBr(Li3OBr)2 exhibit mechanical brittleness, which is not conducive to its application as solid electrolytes. Through quasi-harmonic approximation, we found that the linear thermal expansion coefficient of LiBr(Li2OHBr)2 is 2.07 × 10−5 K−1, which is more advantageous in matching electrodes than LiBr(Li3OBr)2 and even simple antiperovskites. Overall, our research provides comprehensive insights into the practical application of R–P antiperovskite in solid-state batteries. [ABSTRACT FROM AUTHOR]

With the global population growth and increasing food demand, the development of precision agriculture has become particularly critical. In precision agriculture, accurately identifying areas of nitrogen stress in crops and planning precise fertilization paths are crucial. However, traditional coverage path-planning (CPP) typically considers only single-area tasks and overlooks the multi-area tasks CPP. To address this problem, this study proposed a Regional Framework for Coverage Path-Planning for Precision Fertilization (RFCPPF) for crop protection UAVs in multi-area tasks. This framework includes three modules: nitrogen stress spatial distribution extraction, multi-area tasks environmental map construction, and coverage path-planning. Firstly, Sentinel-2 remote-sensing images are processed using the Google Earth Engine (GEE) platform, and the Green Normalized Difference Vegetation Index (GNDVI) is calculated to extract the spatial distribution of nitrogen stress. A multi-area tasks environmental map is constructed to guide multiple UAV agents. Subsequently, improvements based on the Double Deep Q Network (DDQN) are introduced, incorporating Long Short-Term Memory (LSTM) and dueling network structures. Additionally, a multi-objective reward function and a state and action selection strategy suitable for stress area plant protection operations are designed. Simulation experiments verify the superiority of the proposed method in reducing redundant paths and improving coverage efficiency. The proposed improved DDQN achieved an overall step count that is 60.71% of MLP-DDQN and 90.55% of Breadth-First Search–Boustrophedon Algorithm (BFS-BA). Additionally, the total repeated coverage rate was reduced by 7.06% compared to MLP-DDQN and by 8.82% compared to BFS-BA. [ABSTRACT FROM AUTHOR]

Kagome materials serve as crucial platforms for investigating the quantum anomalous Hall effect (QAHE) due to the presence of kagome bands in their electronic structures. However, despite the theoretical predictions being proposed, kagome band material realizations have been limited. In this work, through tight-binding (TB) model analysis, by setting the nearest-neighbor hopping integrals with opposite signs, we propose a Yin–Yang kagome band structure characterized by two stable enantiomorphic kagome bands. Furthermore, we design a monolayer V3Cl6 to confirm the TB model. Three V atoms are located in different coordination environments in V3Cl6, so opposite signs of the hopping integrals between two of their orthogonal d orbitals can be achieved, which is the key to realize Yin–Yang kagome band structures. The calculated band structures obtained from first principles are consistent with those from the TB model. Additionally, we find that the two enantiomorphic flat bands in monolayer V3Cl6 possess opposite Chern number after spin–orbit coupling is considered, which can also be confirmed from symmetry index analysis. The Chern numbers as well as the topological properties can be modulated by doping hole or adjusting the magnetization directions, so the QAHE can be tuned in monolayer V3Cl6. Our results provide a practicable pathway for realizing Yin–Yang kagome band structures and achieving tunable QAHE in them. [ABSTRACT FROM AUTHOR]

Two-dimensional intrinsic magnetic topological materials that can realize device miniaturization have attracted significant attention recently based on their chiral dissipationless edge states. However, since the experimental observation of quantum anomalous Hall effect (QAHE) is still limited by low temperature, high operating temperature and large nontrivial gap are urgently needed. Here, monolayer MnAsO3 is predicted to be a room-temperature intrinsic magnetic topological material with high Chern number C = 3 based on first-principles calculations, which offers the possibility of achieving high-speed and low-energy-consumption electron transport in the future. Furthermore, the large and experimental feasible nontrivial gap up to 79.09 meV is obtained under compressive strain modulation. Moreover, the high-Chern-number topological phase transition and strain-induced spin-unlocked edge states are observed, indicating the possibility of tuning the electron transport of QAHE. All these findings suggest that monolayer MnAsO3 is a suitable and promising material for fabricating low-energy-consumption spintronics devices. [ABSTRACT FROM AUTHOR]