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How crystallization additives govern halide perovskite grain growth
No full textThe preparation of perovskite solar cells from the liquid phase is a cornerstone of their immense potential. However, a clear relationship between the precursor ink and the formation of the resulting perovskite is missing. Established theories, such as heterogeneous nucleation and lead complex colloid formation, often prove unreliable, which has led to an overreliance on heuristics. Most high-performing perovskites use additives to control crystallization. Their role during crystallization is, however, elusive. Here, we provide evidence that typical crystallization additives do not predominantly impact the nucleation phase but rather facilitate coarsening grain growth by increasing ion mobility across grain boundaries. Drawing from the insights of our broad, interdisciplinary study that combines ex and in situ characterization methods, devices, simulations, and density function theory calculation, we propose a concept that proves valid for various additives and perovskite formulations. Moreover, we establish a direct link between additive engineering and perovskite post-processing, offering a unified framework for advancing material design and process engineering
Correction: Enhancing the thermoelectric figure of merit of BiN via polymorphism, pressure, and nanostructuring
No full textCorrection for ‘Enhancing the thermoelectric figure of merit of BiN via polymorphism, pressure, and nanostructuring’ by Elena R. Remesal et al., J. Mater. Chem. A, 2025, 13, 220–229, https://doi.org/10.1039/D4TA05891G.The authors regret that the funding information was incorrectly ordered in the Acknowledgements and they omitted the acknowledgment of the Cover in the published article. The corrected Acknowledgements section should read as follows.Cover: This publication is part of the project TED2021-130874B-I00, funded by MICIU/AEI/10.13039/501100011033 and by the European Union NextGenerationEU/PRTR.This work was funded by grant TED2021-130874B-I00 funded by MICIU/AEI/10.13039/501100011033 and by the “European Union NextGenerationEU/PRTR” and by grant PID2022-138063OB-I00 funded by MICIU/AEI/10.13039/501100011033 and by FEDER, UE. We thankfully acknowledge the computer resources at Lusitania and the technical support provided by Cénits-COMPUTAEX and Red Española de Supercomputación, RES (QHS-2023-1-0028).The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers
Self-gravity in superradiance clouds: Implications for binary dynamics and observational prospects
No full textSpinning black holes could produce ultralight particles via the superradiance instability. These particles form a dense cloud around the host black hole, introducing new opportunities for the detection of ultralight new physics. When the black hole is part of a binary system, the binary can trigger transitions among different states of the cloud configuration. Such transitions backreact on the orbital dynamics, modifying the frequency evolution of the emitted gravitational waves. Based on this observation, black hole binaries were proposed as a way to test the existence of ultralight particles. We investigate the effects of the self-gravity of the cloud on the orbital evolution and on the gravitational wave emission. We find that cloud self-gravity could lead to a density-dependent modification of the energy levels of ultralight particles and that it could alter the order of hyperfine energy levels. The crossing of hyperfine levels prevents binaries from triggering resonant hyperfine transitions, and allows them to approach radii that could trigger resonant transitions of fine levels. We study the implications of these findings, especially in the context of future space-borne gravitational wave observatory, the Laser Interferometer Space Antenna (LISA). For quasicircular, prograde, and equatorial orbits, we find that LISA could probe ultralight particles in the mass range 10-15 eV–10-13 eV through gravitational wave observations
Promising Alloys for Hydrogen Storage in the Compositional Space of (TiVNb)(Cr,Mo) High Entropy Alloys
No full textThis study reports on the search for the most promising alloys in the compositional space of (TiVNb)80Cr20–xMox (x = 5, 10, and 15) and (TiVNb)75Cr25–xMox (x = 5, 10, 15, and 20) high-entropy alloys. First, data-driven machine learning applied to these systems predicts that increasing the Mo content destabilizes the enthalpy of the hydride phases. Second, experimental and density functional theory (DFT) validations were performed. The as-prepared alloys have single-phase bcc lattices and rapidly absorb hydrogen to form fcc-type hydrides with a high capacity between 1.6 and 2.0 H/M. Despite a positive effect on the thermodynamics of the hydride phases, increasing the Mo content in these alloys has a negative effect on the maximum capacity. The cycling experiments highlight the need to balance the reversible capacity, cycle life, and crystalline stabilities of these phases. Therefore, considering all these results, the most promising alloy with trade-off properties within the targeted compositional space has been identified to be (TiVNb)75Cr5Mo20 that shows a maximum capacity of 2.6 wt % (1.8 H/M), a reasonable enthalpy of hydride formation (−38.6 kJ/mol H2), and a notable gravimetric reversible capacity of 1.42 wt % at room temperature. To identify the most promising high-entropy alloys for this application, integrated machine learning predictions followed by experimental and DFT validations proved to be an effective strategy
Antiferromagnet-topological insulator heterostructure for polarization-controllable terahertz generation
No full textAntiferromagnets (AFMs) are more advantageous in realizing ultrafast spin-based processes, but remain challenging to manipulate. The lack of proper knobs in AFM-based ultrafast devices greatly hampers their applications. Here, we innovate an antiferromagnet/topological insulator (AFM/TI) heterostructure MnSe/(Bi,Sb)2Te3 to realize laser-induced transient magnetic moment, and further demonstrate optically controllable circularly polarized ultrafast terahertz (THz) pulse generation, under zero external magnetic field. Intriguingly, we find two mechanisms underlying the ultrafast THz pulse generation: direct magnetic dipole radiation and spin-charge conversion resulted electric dipole radiation. Our findings provide a suitable platform for efficient and polarization-controllable ultrafast THz devices via optical means
CP violation in decays into states with neutral kaons
No full textCP violation in the kaon system can manifest itself in decays to final states containing neutral kaons. The effect is governed by an efficiency function that reflects the specific experimental setup. We demonstrate that this efficiency function factorizes into two components: the kaon energy spectrum and a universal detector-dependent factor. We show that matter effects on kaon oscillations can have a significant effect on CP asymmetries. We provide estimates of the theoretical prediction for some such CP asymmetries for a Belle II-type experiment
Progress and Bottlenecks for Deep Learning in Computational Structure Biology: CASP Round XVI
No full textCASP16 is the most recent in a series of community experiments to rigorously assess the state of the art in areas of computational structural biology. The field has advanced enormously in recent years: in early CASPs, the assessments centered around whether the methods were at all useful. Now they mostly focus on how near we are to not needing experiments. In most areas, deep learning methods dominate, particularly AlphaFold variants and associated technology. In this round, there is no significant change in overall agreement between calculated monomer protein structures and their experimental counterparts, not because of method deficiencies but because, for most proteins, agreement is likely as high as can be obtained given experimental uncertainty. For protein complexes, huge gains in accuracy were made in the previous CASP, but there still appears to be room for further improvement. In contrast to these encouraging results, for RNA structures, the deep learning methods are notably unsuccessful at present and are not superior to traditional approaches. Both approaches still produce very poor results in the absence of structural homology. For macromolecular ensembles, the small CASP target set limits conclusions, but generally, in the absence of structural templates, results tend to be poor and detailed structures of alternative conformations are usually of relatively low accuracy. For organic ligand–protein structures and affinities (important for aspects of drug design), deep learning methods are substantially more successful than traditional ones on the relatively easy CASP target set, though the results often fall short of experimental accuracy. In the less glamorous but essential area of methods for estimating the accuracy, previous results found reliable accuracy estimates at the amino acid level. The present CASP results show that the best methods are also largely effective in selecting models of protein complexes with high interface accuracy. Will upcoming method improvements overcome the remaining barriers to reaching experimental accuracy in all categories? We will have to wait until the next CASP to find out, but there are two promising trends. One is the combination of traditional physics-inspired methods and deep learning, and the other is the expected increase in training data, especially for ligand–protein complexes
A post-inflationary kinetic axion
No full textWe present a novel realization of axion kinetic misalignment, triggered by a Hubble-induced phase transition during a post-inflationary stiff (kination) era. A negative Ricci scalar flips the sign of a non-minimally coupled mass term for a non-minimally coupled complex field , driving its radial mode to large amplitudes via a tachyonic instability. At large , higher-dimensional -breaking operators become relevant and impart a kick in the angular direction, generating a conserved charge that sustains rotation as the symmetry is approximately restored. Because phases randomize across causally disconnected regions, multiple domains with distinct charges form. The subsequent axion potential converts the domain charges into an axion abundance, yielding dark matter even when the net global charge vanishes. We analyze the dynamics through a linear, domain-averaged treatment and identify two thermal histories: (i) Ricci reheating via saxion decays to Higgs bosons; (ii) external reheating with efficient damping of saxion energy by Higgs/fermion scatterings. The mechanism populates regions underabundant in standard misalignment, which are accessible to next generation axion searches
Measurements of electroweak production of a photon in association with two jets in proton-proton collisions at = 13 TeV
No full textThe first observation of electroweak production of a photon in association with two forward jets in proton-proton collisions is presented. The measurement uses data recorded by the CMS experiment at the LHC during 20162018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb. The analysis is performed in a region enriched in photon production via vector boson fusion, with a requirement on the transverse momentum of the photon to exceed 200 GeV. The cross section is measured to be 202 fb, at a significance with respect to the null hypothesis that exceeds five standard deviations. This is in agreement with the standard model prediction of 177 fb. Differential cross sections are measured as a function of various observables. Limits are set on dimension-6 effective field theory operators that contribute to the WW interaction. The observed 95% confidence intervals for the corresponding Warsaw basis Wilson coefficients and are [0.11, 0.16] and [1.6, 1.5], respectively