Floquet Engineering of Nonequilibrium Valley-Polarized Quantum Anomalous Hall Effect with Tunable Chern Number.

Here, we propose that Floquet engineering offers a strategy to realize the nonequilibrium quantum anomalous Hall effect (QAHE) with tunable Chern number. Using first-principles calculations and Floquet theorem, we unveil that QAHE related to valley polarization (VP-QAHE) is formed from the hybridization of Floquet sidebands in the two-dimensional family Si (M = Mo, W, V; = N, P, As) by irradiating circularly polarized light (CPL). Through the tuning of frequency, intensity, and handedness of CPL, the Chern number of VP-QAHE is highly tunable and up to = ±4, which attributes to light-induced trigonal warping and multiple-band inversion at different valleys.

Distributional Characteristics and Source Identification of Cadmium in Soils of the Pearl River Delta, China.

The results of the Multi-Purpose Geochemical Survey in the Pearl River Delta (PRD) show that the pollution is serious. In this study, the influence of geological genesis, soil-forming process, and human activities on soil quality in PRD is analyzed, and the influence factors, genesis and spatial distributional characteristics of cadmium (Cd) in different soil depths are studied by inverse distance weighted (IDW) and hot spot analysis. The results show that the spatial distribution of Cd is significantly different in PRD and high-value is mainly concentrated in the central cities of Guangzhou-Foshan-Jiangmen-Zhongshan-Zhuhai.

Evaluation of heavy metal distribution characteristics of agricultural soil-rice system in a high geological background area according to the influence index of comprehensive quality (IICQ).

Heavy metal pollution is a global ecological safety issue, especially in crops, where it directly threatens regional ecological security and human health. Selecting scientific evaluation methods is an important prerequisite for understanding the distribution of heavy metals in a region. To evaluate the distribution characteristics of arsenic (As), cadmium (Cd), copper (Cu), and zinc (Zn) in farmland soil-rice system in Doumen District of Zhuhai City, Pearl River Delta, we analyzed the high geological background area and heavy metal contents in soil by inverse distance-weighted interpolation and single-factor pollution index.

Discovery of a magnetic conductive interface in PbZrTiO /SrTiO heterostructures.

Emergent physical properties often arise at interfaces of complex oxide heterostructures due to the interplay between various degrees of freedom, especially those with polar discontinuities. It is desirable to explore if these structures may generate pure and controllable spin currents, which are needed to attain unmatched performance and energy efficiency in the next-generation spintronic devices. Here we report the emergence of a spin-polarized two-dimensional electron gas (SP-2DEG) at the interface of two insulators, SrTiO and PbZrTiO.

Above 400-K robust perpendicular ferromagnetic phase in a topological insulator.

The quantum anomalous Hall effect (QAHE) that emerges under broken time-reversal symmetry in topological insulators (TIs) exhibits many fascinating physical properties for potential applications in nanoelectronics and spintronics. However, in transition metal-doped TIs, the only experimentally demonstrated QAHE system to date, the QAHE is lost at practically relevant temperatures. This constraint is imposed by the relatively low Curie temperature () and inherent spin disorder associated with the random magnetic dopants.