"Mn3AlN" is Really Mn4N.

We investigate the synthesis of antiperovskite "Mn3AlN" using the published synthesis procedure, as well as several new reaction pathways. In each case, only a combination of antiperovskite Mn4N and Mn5Al8 or precursors is obtained. The identity of the obtained antiperovskite phase is unambiguously determined to be Mn4N via synchrotron powder X-ray diffraction (SPXRD), X-ray absorption spectroscopy (XAS), and magnetometry. The experimental results are further supported by thermochemical calculations informed by density functional theory (DFT), which find Mn3AlN to be metastable versus decomposition into Mn and AlN. The DFT-based calculations also predict an antiferromagnetic ground state for Mn3AlN. This directly contradicts the previously reported ferromagnetic behavior of "Mn3AlN". Instead, the observed magnetic behavior is consistent with ferrimagnetic Mn4N. We examine the data in the original publication and conclude that the compound reported to be Mn3AlN is in fact Mn4N.

Enhanced carrier densities in two-dimensional electron gas formed at BaSnO3/SrTaO3and SrSnO3/SrTaO3interfaces.

Two-dimensional electron gases (2DEGs) realized at perovskite oxide interfaces offer great promise for high charge carrier concentrations and low-loss charge transport. BaSnO3(BSO) and SrSnO3(SSO) are well-known wide bandgap semiconductors for their high mobility due to the Sn-5s-dominated conduction band minimum (CBM). Ta4+with a 5d1valence configuration in SrTaO3(STaO) injects thed1electron across the interface into the unoccupied Sn-5sstates in BSO and SSO. The present study uses ACBN0 density functional theory computations to explore charge transfer and 2DEG formation at BSO/STaO and SSO/STaO interfaces. The results of the ACBN0 computations confirm the Ta-5dto Sn-5scharge transfer. Moreover, the Sn-5s-dominated CBM is located ∼1.4 eV below the Fermi level, corresponding to an excess electron density in BSO of ∼1.5 × 1021cm-3, a ∼50% increase in electron density compared to the previously studied BSO/SrNbO3(SNO) interface. Similarly, the SSO/STaO interface shows an improvement in interface electron density by ∼20% compared to the BSO/SNO interface. The improved carrier density in SSO/STaO and BSO/STaO is further supported by ∼13% and ∼15% increase in electrical conductivities compared to BSO/SNO. In summary, BSO/STaO and SSO/STaO interfaces provide novel material platforms for 2DEGs formation and ultra-low-loss electron transport.

A comparative study on effect of news sentiment on stock price prediction with deep learning architecture.

The accelerated progress in artificial intelligence encourages sophisticated deep learning methods in predicting stock prices. In the meantime, easy accessibility of the stock market in the palm of one's hand has made its behavior more fuzzy, volatile, and complex than ever. The world is looking at an accurate and reliable model that uses text and numerical data which better represents the market's highly volatile and non-linear behavior in a broader spectrum. A research gap exists in accurately predicting a target stock's closing price utilizing the combined numerical and text data. This study uses long short-term memory (LSTM) and gated recurrent unit (GRU) to predict the stock price using stock features alone and incorporating financial news data in conjunction with stock features. The comparative study carried out under identical conditions dispassionately evaluates the importance of incorporating financial news in stock price prediction. Our experiment concludes that incorporating financial news data produces better prediction accuracy than using the stock fundamental features alone. The performances of the model architecture are compared using the standard assessment metrics -Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE), and Correlation Coefficient (R). Furthermore, statistical tests are conducted to further verify the models' robustness and reliability.

High Mobility Two-Dimensional Electron Gas at the BaSnO3/SrNbO3 Interface.

Oxide two-dimensional electron gases (2DEGs) promise high charge carrier concentrations and low-loss electronic transport in semiconductors such as BaSnO3 (BSO). ACBN0 computations for BSO/SrNbO3 (SNO) interfaces show Nb-4d electron injection into extended Sn-5s electronic states. The conduction band minimum consists of Sn-5s states ∼1.2 eV below the Fermi level for intermediate thickness 6-unit cell BSO/6-unit cell SNO superlattices, corresponding to an electron density in BSO of ∼1021 cm-3. Experimental studies of analogous BSO/SNO interfaces grown by molecular beam epitaxy confirm significant charge transfer from SNO to BSO. In situ angle-resolved X-ray photoelectron spectroscopy studies show an electron density of ∼4 × 1021 cm-3. The consistency of theory and experiments show that BSO/SNO interfaces provide a novel materials platform for low loss electron transport in 2DEGs.

Layer dependent magnetism and topology in monolayer and bilayers ReX3(X=Br, I).

The realization of robust intrinsic ferromagnetism in two-dimensional materials with the possibility to support topologically non-trivial states has provided the fertile ground for novel physics and next-generation spintronics and quantum computing applications. In this contribution, we investigated the formation of topological states and magnetism in monolayer and bilayer systems of ReX3(X= Br, I), with PBE, ACBN0 (self-consistent Hubbard-U), excluding/including van der Waals (vdW) corrections and/or spin-orbit coupling. Bulk ReX3(X= Br, I) is predicted to crystallize in space groupR3¯(#148), similar to CrI3, with monolayer exfoliation energies that are comparable or less than that of graphite. The topological character of the monolayer and bilayer systems of ReX3(X= Br, I) is derived from anomalous Hall conductivity computations. Topologically non-trivial states in ReX3(X= Br, I) are absent in the Hubbard-Ucomputations if vdW interactions are included, a prediction that is attributed to the large Hubbard-Udifference between the chemical constituents, ΔU∼ 1.5-1.6 eV, and a significant ∼2.0%-3.6% compressive in-plane strain introduced by vdW interactions. In contrast to the fragile and likely absent topological states in ReX3(X= Br, I), magnetic properties are robust and independent of the level of theory: ferromagnetic monolayers are coupled antiferromagnetically to bilayers, with an energy separation between ferromagnetic and antiferromagnetic bilayer spin configurations that could be as low as 0.02 meV/Re (f= 4.8 GHz), well within the microwave range. This suggests that layer dependent magnetism in ReX3(X= Br, I) may support a microwave controllable magnetic qubit, consisting of a superposition of antiferromagnetic and ferromagnetic bilayer states.

Does ß-PbO2 harbor topological states?

The electronic properties of ß-PbO2, have been controversial for several decades. Experiments find behavior ranging from metallic, attributed to oxygen vacancies, to indirect semiconducting for stoichiometric samples with a gap of 0.61 eV. Theory leads to similar ambiguities, and predicts this phase to be metallic (PBE, HSE06) or to possess a small bandgap (HSE06). An area where this inconsistency is amplified, is when a material behavior depends on the electronic structure in the vicinity of the Fermi energy, such as topological states. In our work, we use a self-consistent DFT + U approach and find that stoichiometric ß-PbO2 to be an indirect semiconductor with a band gap of ∼0.8 eV, similar to experiment. The larger bandgap requires at least ∼4% strain, to drive ß-PbO2 into a nodal line semimetallic state, significantly larger strains than reported previously. Moreover, we find that the nodal line semimetallic state is not protected against spin-orbit-coupling. Also, the surface computations do not show any evidence for topologically protected states near the Fermi energy. Therefore, our results strongly suggest that ß-PbO2 is a topologically trivial material, consistent with experiment, but in stark contrast to previous computations. Previously reported topologically protected states in ß-PbO2 are attributed to an inaccurate description of the (bulk) optical properties.