The Generation of Switchable Polarized Currents in Nodal Ring Semimetals Using High-Frequency Periodic Driving

A nodal ring semimetal (NRSM) can be driven to a spin-polarized NRSM or a spin-polarized Weyl semimetal (SWSM) by a high-frequency electromagnetic field. We investigate the conditions in realizing these phases and propose a switchable spin-polarized currents generator based on periodically driven NRSMs. Both bulk and surface polarized currents are investigated. The polarization of bulk current is sensitive to the amplitude of the driving field and robust against the direction and polarization of the driving, the opaqueness of the lead-device interface and the misalignment between the nodal ring and the interface, which provides sufficient flexibility in manipulating the devices. Similar switchable polarized surface currents are also expected, which is contributed by the Fermi arc surface state associated with the Weyl semimetal (WSM) phases. The generation of polarized currents and the polarization switching effect offer opportunities to design periodic driving controlled topological spintronics devices based on NRSMs.

Resistance Switching Effect of Memory Device Based on All-Inorganic Cspbbri2 Perovskite

In this study, the CsPbBrI2 perovskite film was prepared by the preparation of the sol-gel and the spin-coating method, and the cubic lattice was stabilized by introducing Br+ into the CsPbI3 film, which solved the problem of instability of the traditional perovskite phase. Based on the CsPbBrI2 perovskite film, the Ag/CsPbBrI2/ITO memory device with a resistance switching effect was prepared. The morphology and phase compositions of the film were analyzed by scanning electron microscope and X-ray diffraction. The non-volatile and repeatable resistance switching effect of the Ag/CsPbBrI2/ITO memory device was measured under open-air conditions. The experimental results show that the surface of the CsPbBrI2 perovskite film is uniform and dense, and the Ag/CsPbBrI2/ITO memory device has an order of magnitude resistance-on-off ratio after 500 cycles of cyclic voltage. This study shows that Ag/CsPbBrI2/ITO memory devices based on CsPbBrI2 perovskite films have potential applications in the field of non-volatile memory devices. At the same time, the transient properties of the CsPbBrI2 film that can quickly dissolve in deionized water make it potentially useful in short-period data storage units and implantable electronic devices with human or environmental sensors.

Factors that motivate ecuadorian public school english teachers to code-switch in the english as foreign language classroom

Code-switching is a sociolinguistic phenomenon that usually occurs in bilingual or multilingual communities. Regarding English Language teaching contexts, it seems that code-switching also occurs in EFL classrooms. Therefore, this paper attempts to find out and describe the factors that motivate Ecuadorian English teachers to code-switch as well as establish the foundation for further researches about the code-switching effect and the role that L1 should play in the EFL classroom. This descriptive, combined, and ethnographic research gathered data through a surveys compound by 6 questions framing the Likert scale, which were answered by 17 Ecuadorian English teachers. The results show that the factors that motivate them to code-switch are related to pedagogical and affective purposes; nevertheless, it seems that its usage is neither planned nor applied to get pedagogical purposes that let them know how and when code-switching might enhance the SLA process.