The term quantum materials refers to materials whose properties are principally defined by quantum mechanical effects at macroscopic length scales and that exhibit phenomena and functionalities not expected from classical physics. Some key characteristics include reduced dimensionality, strong many-body interactions, nontrivial topology, and noncharge state variables of charge carriers. The field of quantum materials has been a topical area of modern materials science for decades, and is at the center stage of a wide range of modern technologies, ranging from electronics, photonics, energy, defense, to environmental and biomedical sensing. Over the past decade, much research effort has been devoted to the development of quantum materials with phenomena and functionalities that manifest at high temperature and feature unprecedented tunability with atomic-scale precision. This thriving research field has witnessed a number of seminal breakthroughs and is now poised to rise to the challenges in a new age of quantum information science and technology. This issue summarizes and reviews recent progress in selected topics, and also provides perspective for the future directions of emergent quantum materials in the years to come.

An indirect exciton (IX), also known as an interlayer exciton, is a bound pair of an electron and a hole confined in spatially separated layers. Due to their long lifetimes, IXs can cool below the temperature of quantum degeneracy. This provides an opportunity to experimentally study cold composite bosons. This article overviews our studies of cold IXs, presenting spontaneous coherence and Bose–Einstein condensation of IXs and phenomena observed in the IX condensate, including the spatially ordered exciton state, commensurability effect of exciton density wave, spin textures, Pancharatnam–Berry phase, long-range coherent spin transport, and interference dislocations.

This report is on the synthesis by electrospinning of multiferroic core-shell nanofibers of strontium hexaferrite and lead zirconate titanate or barium titanate and studies on magneto-electric (ME) coupling. Fibers with well-defined core–shell structures showed the order parameters in agreement with values for nanostructures. The strength of ME coupling measured by the magnetic field-induced polarization showed the fractional change in the remnant polarization as high as 21%. The ME voltage coefficient in H-assembled films showed the strong ME response for the zero magnetic bias field. Follow-up studies and potential avenues for enhancing the strength of ME coupling in the core–shell nanofibers are discussed.

Here, the authors report a detailed method of growing LaAlGe, a nonmagnetic Weyl semimetal, thin film on silicon(100) substrates by molecular beam epitaxy and their structural and electrical characterizations. About 50-nm-thick LaAlGe films were deposited and annealed for 16 h in situ at a temperature of 793 K. As-grown high-quality films showed uniform surface topography and near ideal stoichiometry with a body-centered tetragonal crystal structure. Temperature-dependent longitudinal resistivity can be understood with dominant interband s–d electron–phonon scattering in the temperature range of 5–40 K. Hall measurements confirmed the semimetallic nature of the films with an electron-dominated charge carrier density of ~7.15 × 1021 cm−3 at 5 K.

β-Alanine and its derivatives are important starting materials for the preparation of peptides or compounds with biological activity. In this work, the authors are presenting a new approach for the synthesis of N-alkyl-β-amino acids and N-alkyl-β-amino esters using dendrimeric intermediates in a one-pot reaction, with friendly reaction conditions. Dendrimeric compounds, with a pentaerythritol core, were easy prepared and used to obtain the β-amino acid derivatives and β-amino esters with good yields. This paper presents the first reaction where dendrimers are used for synthesizing organic compounds. Spectroscopic characterization by 1H- and 13C-NMR of dendrimers and final products is also presented.

The lifetime of cyclically loaded devices is often limited by the fatigue resistance of their individual phases. An advanced method is presented for measuring the high-cycle fatigue behavior of materials at the micrometer scale using a nanoindenter. It is based on the cyclic deflection of focused ion beam-fabricated microcantilevers using the continuous stiffness method (CSM). In line with experimental data on bulk nanocrystalline copper, the specimens exhibit grain coarsening followed by the formation of extrusions and a fatigue strength exponent of −0.10. The method is suitable for characterizing single phases and individual components of further complex systems.

The remarkable progress in additive manufacturing has promoted the design of architected materials with mechanical properties that go beyond those of conventional solids. Their realization, however, leads to architectures with process-induced defects that can jeopardize mechanical and functional performance. In this work, we investigate experimentally and numerically as-manufactured defects in Ti–6Al–4V octet truss lattice materials fabricated with selective laser melting. Four sets of as-manufactured defects, including surface, microstructural, morphological, and material property imperfections, are characterized experimentally at given locations and orientations. Within the characterized defects, material property and morphological defects are quantified statistically using a combination of atomic force microscopy and micro–computed tomography to generate representative models that incorporate individual defects and their combination. The models are used to assess the sensitivity to as-manufactured defects. Then, the study is expanded by tuning defects amplitude to elucidate the role of the magnitude of as-designed defects on the mechanical properties of the lattice material.

Dissolution of oxides in aqueous solutions is fundamentally important for a range of applications and a critical process that determines the chemical durability of industrial ceramics, the performance of nuclear waste forms, and the chemical weathering of minerals. The thermodynamic equilibrium and kinetics of dissolution reactions are key to determining the rate at which oxides dissolve. The increase in collaborative research across disciplines in materials research necessitates a common background to tackle shared scientific problems across different fields. This review selectively examines the fundamentals of dissolution theories that have been developed in chemistry, geochemistry, and materials science, and assembles them into a single collective document for the broader materials science community. Applications of the theories are highlighted using examples from specific areas, but can be similarly applied to other areas. Challenges and future research needs for a predictive-level understanding are discussed in light of the current literature.