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Two-dimensional topological insulators hosting the quantum spin Hall effect have application potential in dissipationless electronics. To observe the quantum spin Hall effect at elevated temperatures, a wide band gap is indispensable to efficiently suppress bulk conduction. Yet, most candidate materials exhibit narrow or even negative band gaps. Here, via elegant control of van der Waals epitaxy, we have successfully grown monolayer ZrTe5 on a bilayer graphene/SiC substrate. The epitaxial ZrTe5 monolayer crystalizes in two allotrope isomers with different intralayer alignments of ZrTe3 prisms. Our scanning tunneling microscopy/spectroscopy characterization unveils an intrinsic full band gap as large as 254 meV and one-dimensional edge states localized along the periphery of the ZrTe5 monolayer. First-principles calculations further confirm that the large band gap originates from strong spin−orbit coupling, and the edge states are topologically nontrivial. These findings thus provide a highly desirable material platform for the exploration of the high-temperature quantum spin Hall effect.Quantum spin Hall materials hold great potential for future nanoelectronics. Here, authors synthesize a potential host system — monolayer ZrTe5 — and demonstrate it possesses a band gap wide enough for potential room-temperature applications. [ABSTRACT FROM AUTHOR]

Recent studies have shown that a rich variety of exotic physical phenomena can emerge from the presence of electronic flat bands. Using first‐principles calculations, here a monolayered Ca2C possesses a relatively flat band near the Fermi level, and across the whole Brillouin zone is predicted. Next, the weak d0 ferromagnetism in Ca2C is substantially enhanced by a proximity‐coupled electride monolayer of Ca2N is shown. The enhanced magnetism can be attributed to the straightening of the flat band caused by the charge transfer to the electride, while the flattening is tied to the magic ratio of three between the σ and π channels of the effective C─C coupling strength. More surprisingly, even though each of the constituent systems is topologically trivial, the Ca2C/Ca2N heterobilayer is empowered with nontrivial band topology, characterized by a high Chern number tunable by the magnetization orientation or lateral strain. These findings provide a new platform for realizing intriguing magnetic topological metals in 2D materials. [ABSTRACT FROM AUTHOR]

This paper modeled forced and free vibrations of an axially functionally graded (AFG) porous Rayleigh nanotube containing fluid surrounded by a viscoelastic foundation and acted by a traveling load. The material characteristics of the nanotube are graded longitudinally according to a power-law rule. Also, different porosity models in the longitudinal direction of the system are taken into account. The nonlocal strain gradient theory (NSGT) is applied to reflect the size-dependency of the model. The governing dynamic equation of the system incorporating the scale effects is derived by considering the effects of slip boundary conditions for the internal fluid. The vibration response of the system is obtained analytically. Several comparison studies verify this study's results. Various dynamic phenomena, such as cancellation and maximum free response, are discussed in different operating conditions of the system. Besides, a detailed parametric investigation is conducted to identify the effects of influential parameters, including material gradient, porosity coefficient, fluid velocity, scale parameter ratio, and substrate characteristics, on the dynamic behavior of the system. These research results could be valuable in designing and optimizing advanced nanosensors and targeted drug delivery systems. [ABSTRACT FROM AUTHOR]

This study investigates the linkage from income class to pro-environmental behaviour among people with different income levels. By setting a hierarchical regression model and using data from the World Value Survey (WVS), this study finds that higher income reinforces pro-environmental behaviour. In addition, income satisfaction significantly strengthen the relationship between income class and pro-environmental behaviour, such that the link between them gets stronger when the individuals are satisfied with their income. The findings show that income level and income satisfaction go hand-in-hand in bringing about pro-environmental engagement. [ABSTRACT FROM AUTHOR]

Torsion deformable spatial beam and Costello theory are used to establish longitudinal-torsional-lateral coupled model of round balance rope. Based on Coulomb's friction law and longitudinal-torsional-lateral coupled model, the nonlinear coupled dynamic model with friction constraint of round balance rope is established. Meanwhile, time-varying multi-segments non–equal-length element transformation method (TMN-ETM) is proposed to save computation time. Then, natural frequencies, lateral responses are calculated when the coupled stiffness coefficient is zero. And the calculations are compared with traditional solution method. The results show that only about few areas in the round balance rope loop have large stress norm value, while the rest parts have small stress values. Besides, dynamic responses of the balance rope with balance rope suspension rotor releasing are conducted. When the static friction is converted to dynamic friction, the friction torque and angle acceleration will be mutated at the switching instants, and slip-stick transition in angle acceleration occurs. [ABSTRACT FROM AUTHOR]