No abstract

Spin-orbit coupling (SOC) plays a crucial role for spintronics applications. Here we present the first demonstration that the Rashba SOC at the SrTiO-based interfaces is highly tunable by photoinduced charge doping, that is, optical gating. Such optical manipulation is nonvolatile after the removal of the illumination in contrast to conventional electrostatic gating and also erasable via a warming-cooling cycle. Moreover, the SOC evolutions tuned by illuminations with different wavelengths at various gate voltages coincide with each other in different doping regions and collectively form an upward-downward trend curve: In response to the increase of conductivity, the SOC strength first increases and then decreases, which can be attributed to the orbital hybridization of Ti 3d subbands. More strikingly, the optical manipulation is effective enough to tune the interferences of Bloch wave functions from constructive to destructive and therefore to realize a transition from weak localization to weak antilocalization. The present findings pave a way toward the exploration of photoinduced nontrivial quantum states and the design of optically controlled spintronic devices.

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Afforestation‐induced changes in water resources have attracted worldwide attention. However, a clear picture of quantitative attribution of terrestrial water storage (TWS) variation from hydroclimatic and anthropogenic factors is still lacking. In this study, a quantitative analysis of TWS variation was conducted in the Yellow River basin of China under the Grain for Green project with consideration of irrigation. The results showed that the TWS has decreased (increased) more and more quickly (slowly) in the Loess Plateau (headwater region). The TWS increase corresponded to increased runoff and soil moisture in the headwaters, and the TWS depletion corresponded to decreased runoff and groundwater in the Loess Plateau and downstream regions. Regarding the TWS change (TWSC), it exhibited a negative trend across the basin. The increase in evapotranspiration (ET) dominated the basin‐averaged TWSC reduction, while the increase in ET was highly related to the increases in vegetation cover and irrigation water use. For spatial TWSC variations, the value of precipitation minus ET could account for most changes in TWSC, except for those in the headwater region and a region near the internally drained area. The increased vegetation coverage, which can affect multiple hydrological processes, played an important role in these two excluded regions. Importantly, the irrigation‐induced TWSC was considerable and varied with different irrigation water sources (i.e., surface water and groundwater). Overall, the impacts of afforestation and irrigation on TWS are sufficiently important. The research in this study can provide guidance for the water resource management during revegetation efforts.