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There are many electronic and magnetic properties exhibited by complex oxides. Electronic phase separation (EPS) is one of those, the presence of which can be linked to exotic behaviours, such as colossal magnetoresistance, metal–insulator transition and high-temperature superconductivity. A variety of new and unusual electronic phases at the interfaces between complex oxides, in particular between two non-magnetic insulators LaAlO 3 and SrTiO 3 , have stimulated the oxide community. However, no EPS has been observed in this system despite a theoretical prediction. Here, we report an EPS state at the LaAlO 3 /SrTiO 3 interface, where the interface charges are separated into regions of a quasi-two-dimensional electron gas, a ferromagnetic phase, which persists above room temperature, and a (superconductor like) diamagnetic/paramagnetic phase below 60 K. The EPS is due to the selective occupancy (in the form of 2D-nanoscopic metallic droplets) of interface sub-bands of the nearly degenerate Ti orbital in the SrTiO 3 . The observation of this EPS demonstrates the electronic and magnetic phenomena that can emerge at the interface between complex oxides mediated by the Ti orbital. Interface effects in complex oxides could have interesting technological applications. Ariando et al. demonstrate electronic phase separation and rich physics at a complex oxide interface between the two non-magnetic insulators LaAlO 3 and SrTiO 3 .

Electronic correlations play important roles in driving exotic phenomena in condensed matter physics. They determine low-energy properties through high-energy bands well-beyond optics. Great effort has been made to understand low-energy excitations such as low-energy excitons in transition metal dichalcogenides (TMDCs), however their high-energy bands and interlayer correlation remain mysteries. Herewith, by measuring temperature- and polarization-dependent complex dielectric and loss functions of bulk molybdenum disulphide from near-infrared to soft X-ray, supported with theoretical calculations, we discover unconventional soft X-ray correlated-plasmons with low-loss, and electronic transitions that reduce dimensionality and increase correlations, accompanied with significantly modified low-energy excitons. At room temperature, interlayer electronic correlations, together with the intralayer correlations in the c -axis, are surprisingly strong, yielding a three-dimensional-like system. Upon cooling, wide-range spectral-weight transfer occurs across a few tens of eV and in-plane p–d hybridizations become enhanced, revealing strong Coulomb correlations and electronic anisotropy, yielding a two-dimensional- like system. Our result shows the importance of strong electronic, interlayer and intralayer correlations in determining electronic structure and opens up applications of utilizing TMDCs on plasmonic nanolithrography. Electronic and interlayer correlations are expected to affect the electronic and optical properties of transition metal dichalcogenides. Here, by using spectroscopic ellipsometry in the broad energy range, the authors uncover new electronic transitions and correlated plasmons in bulk MoS 2 .

The Brantas Watershed located in East Java has the vulnerability of drought as one of hydrometeorological disasters. The Vegetation Health Index (VHI) as one of remote sensing index was used to analyse drought. VHI can be derived based on both the Land Temperature Surface (LST) and Normalized Differenced Vegetation Index (NDVI). This research aimed to determine the influence of LST and NDVI, respectively, to VHI, especially in dry season of 2008 - 2017. The data used were MODIS Vegetation Indices (MOD13A1) and MODIS Land Surface Temperature (MOD11B1). The influence of LST and NDVI to VHI in the Brantas Watershed was analysed using correlation and regression testing. The LST - NDVI correlation of Brantas Watershed was negative (-0.73). The high temperature distribution was dominantly located in the low-density vegetation areas. The LST - VHI correlation was 0.35, and NDVI - VHI correlation was 0.63. This illustrated that the influence of land surface temperature to the vegetation drought was weak. Drought indicated by VHI was more likely to be influenced by internal conditions of vegetation and other environmental elements.

Semiconductor compounds are widely used for photocatalytic hydrogen production applications, where photogenerated electron–hole pairs are exploited to induce catalysis. Recently, powders of a metallic oxide (Sr 1− x NbO 3 , 0.03< x <0.20) were reported to show competitive photocatalytic efficiencies under visible light, which was attributed to interband absorption. This discovery expanded the range of materials available for optimized performance as photocatalysts. Here we study epitaxial thin films of SrNbO 3+ δ and find that their bandgaps are ∼4.1 eV. Surprisingly, the carrier density of the conducting phase exceeds 10 22  cm −3 and the carrier mobility is only 2.47 cm 2  V −1  s −1 . Contrary to earlier reports, the visible light absorption at 1.8 eV (∼688 nm) is due to the plasmon resonance, arising from the large carrier density. We propose that the hot electron and hole carriers excited via Landau damping (during the plasmon decay) are responsible for the photocatalytic property of this material under visible light irradiation. Metallic oxide SrNbO 3 has been identified as an efficient hydrogen evolution photocatalyst. Here, Venkatesan and co-workers show that its visible light absorption stems from plasmon resonance, thanks to its large carrier density (despite a large 4.1 eV bandgap), as opposed to from an interband transition.

Oil spills pose a persistent threat to marine ecosystems, particularly in East Kalimantan, one of Indonesia’s major oil exploration regions where crude oil distribution and production activities are intensive. However, limited research has quantitatively integrated oil spill trajectory modeling with probabilistic risk assessment for this area. This study aims to fill that gap by modeling oil spill distribution patterns and evaluating their environmental risks under seasonal monsoon conditions. Historical spill records, wind and current data, oil characteristics, and spill parameters were incorporated into the modeling framework. Oil spill dispersion was simulated and validated using Root Mean Square Error (RMSE), which yielded an initial viscosity of 905.88 centipoise, while calibration with the Mean Absolute Percentage Error (MAPE) adjusted the viscosity to 84.3 centipoise. Spill probability was estimated using the Relative Frequency method applied to historical data, and consequences were quantified with Orifice and Bernoulli equations. The results indicate that during the West Monsoon (February 2024), oil tended to spread southwest and northwest, whereas in the East Monsoon (May 2024), the dispersion shifted toward the northwest, north, and northeast. The risk assessment categorized spill probability in the range of 0.1–0.01, with very high consequences due to spill volumes of 10–100 barrels. The novelty of this study findings contribute scientifically by offering a reproducible framework for integrating hydrodynamic modeling and risk analysis, while also providing practical insights for stakeholders such as companies, policymakers, and local communities to design targeted and proactive environmental mitigation strategies.

We report strong ferromagnetism of quasiparticle doped holes both within the ab- plane and along the c- axis of Cu-O planes in low-dimensional Au/ d- La 1.8 Ba 0.2 CuO 4 /LaAlO 3 (001) heterostructures ( d  = 4, 8 and 12 unit-cells) using resonant soft X-ray and magnetic scattering together with X-ray magnetic circular dichroism. Interestingly, ferromagnetism is stronger at a hole doped peak and at an upper Hubbard band of O with spin-polarization degree as high as 40%, revealing strong ferromagnetism of Mottness. For in- ab -plane spin-polarizations, the spin of doped holes in O2 p –Cu3 d –O2 p is a triplet state yielding strong ferromagnetism. For out-of- ab -plane spin-polarization, while the spins of doped holes in both O2 p –O2 p and Cu3 d –Cu3 d are triplet states, the spin of doped holes in Cu3 d –O2 p is a singlet state yielding ferrimagnetism. A ferromagnetic-(002) Bragg-peak of the doped holes is observed and enhanced as a function of d revealing strong ferromagnetism coupling between Cu-O layers along the c -axis. Long-range magnetic order of quasiparticle doped holes is important for understanding the physics of cuprate superconductors, albeit difficult to probe in experiments. Ong et al. observe ferromagnetism of quasiparticle doped holes in a cuprate heterostructure and discuss implications for cuprates in the ground state.

Competition between magnetism and the kinetic energy of mobile carriers (typically holes) in doped antiferromagnets may lead to ‘stripe’ phases 1 , 2 , 3 , 4 , which are charged rivers separating regions of oppositely phased antiferromagnetism. In copper oxides the main experimental evidence for such coexisting static spin and charge order comes from neutron scattering in La 1.48 Nd 0.4 Sr 0.12 CuO 4 (LNSCO; ref.  5 ) and La 1.875 Ba 0.125 CuO 4 (LBCO; ref.  6 ). However, as a neutron is neutral, it does not detect charge but rather its associated lattice distortion 7 , so it is not known whether the stripes involve ordering of the doped holes. Here we present a study of the charge order in LBCO with resonant soft X-ray scattering (RSXS). We observe giant resonances near the Fermi level as well as near the correlated gap 8 , 9 , demonstrating significant modulation in both the doped-hole density and the ‘Mottness’, or the degree to which the system resembles a Mott insulator 10 . The peak-to-trough amplitude of the valence modulation is estimated to be 0.063 holes, which suggests 11 an integrated area of 0.59 holes under a single stripe, close to the expected 0.5 for half-filled stripes.

In condensed matter physics the quasi two-dimensional electron gas at the interface of two different insulators, polar LaAlO 3 on nonpolar SrTiO 3 (LaAlO 3 /SrTiO 3 ) is a spectacular and surprising observation. This phenomenon is LaAlO 3 film thickness dependent and may be explained by the polarization catastrophe model, in which a charge transfer of 0.5 e − from the LaAlO 3 film into the LaAlO 3 /SrTiO 3 interface is expected. Here we show that in conducting samples (≥4 unit cells of LaAlO 3 ) there is indeed a ~0.5 e − transfer from LaAlO 3 into the LaAlO 3 /SrTiO 3 interface by studying the optical conductivity in a broad energy range (0.5–35 eV). Surprisingly, in insulating samples (≤3 unit cells of LaAlO 3 ) a redistribution of charges within the polar LaAlO 3 sublayers (from AlO 2 to LaO) as large as ~0.5 e − is observed, with no charge transfer into the interface. Hence, our results reveal the different mechanisms for the polarization catastrophe compensation in insulating and conducting LaAlO 3 /SrTiO 3 interfaces. The origin of the two-dimensional electron gas at complex oxide interfaces is often explained by the polar catastrophe model, which involves a charge transfer mechanism. Using optical conductivity analysis, the authors assign and quantify the charge transfer, corroborating the polar catastrophe scenario.

Inorganic perovskites have recently attracted much attention as promising new nanocrystalline materials that have interesting fundamental phenomena and great potential in several applications. Herein, we reveal unusual structural and electronic changes in nanocrystalline cesium lead bromide (CsPbBr 3 ) as a function of temperature using high-resolution spectroscopic ellipsometry, high-resolution transmission electron microscopy and terahertz spectroscopy measurements supported by first-principles calculations. New dual phases of crystalline and electronic structures are observed due to the nanocrystalline nature of the material. Interestingly, a change in the electronic structure occurs below 150 K, and the rate at which the nanocrystal transitions from the tetragonal to orthorhombic phase is found to be nonlinear with temperature. Our results show the importance of the charge and lattice interplay in determining the dual phases and fundamental properties of nanocrystalline materials. Nanocrystals: Split personalities bring solar benefits Findings that show nanoscale crystals can adopt multiple properties at low temperatures may aid production of inexpensive solar cells. Crystals such as cesium lead bromide (CsPbBr 3 ) are attractive for next-generation photovoltaics because they can be coated onto numerous types of surfaces. Thomas Whitcher and Andrivo Rusydi from the National University of Singapore and colleagues now report that CsPbBr 3 nanocrystals undergo unusual changes when taken to sub-zero conditions. Through spectroscopic ellipsometry supported with high-resolution electron microscopy and Terahertz spectroscopic measurements, the team identified two different structural arrangements of CsPbBr 3 coexisting at temperatures below −120 °C. By combining the microscopy data of the crystal’s complex refractive index, the researchers found evidence that the two structures also had distinct electrical properties. The new methodology could provide insights into problems that currently affect CsPbBr 3 solar cells, including poor resistance to environmental changes. We reveal unusual electronic and structural changes of nano-crystalline CsPbBr 3 at different temperatures. Using high-resolution spectroscopic ellipsometry, high-resolution transmission electron microscopy, terahertz spectroscopy and supported by first-principles calculations, we find that a new dual structural phase is observed due to an effect of the material’s nano-crystalline nature. We also develop a method of determining the phase transitions within the material through the identification of optical transitions within the electronic structure and the comparison of experimental data and theoretical models. Our result shows the importance of the interplay between charge and lattice in determining structural and electronic properties of nano-crystalline materials.