The study focuses on the systematic growth and characterization of material properties, as well as the low-temperature transport properties, of ultrashallow heavily strained quantum wells. A new characterization method, called Density of Stress Accumulation Points, has been introduced for assessing quantum well strain. An ultrashallow heavily constrained quantum well with a remarkable mobility of 3.382×105 cm${}^2$/Vs was successfully achieved. This achievement serves as the foundation for the development of fully electrically controlled and microwave cavity-coupled quantum dot materials.

In this work, we investigate the effect of strong disorder on BixTeI thin films, revealing a metal-insulator transition that depends on composition and the growth temperature. Understanding how disorder can be used as a parameter to alter the electronic properties of a material goes beyond the conventional understanding of crystalline material conductivity. This study therefore highlights the role of strong localization in disordered materials in shaping emerging quantum properties.

The authors computed bandgaps and formation energy values of more than 1100 crystalline materials‬ using Density Functional Theory (DFT) with HSE‬ and PBE approximations of the pseudopotentials. They analyzed accuracies of HSE and PBE approximations among different classes of materials. They also built a multi-fidelity machine learning model to predict the bandgap at HSE accuracy when a material’s PBE bandgap‬ is known. The new high-throughput DFT (HSE, PBE) data of more than 1100 materials and the predicted‬ HSE bandgap data of more than 21,000 materials are available publicly via a dedicated web app.

α-Sn, the inversion symmetric analogue of HgTe, can be tuned through various topologically non-trivial phases by a combination of strain and/or confinement effects. In addition, thin films of α-Sn have demonstrated very efficient spin-charge conversion. However, α-Sn thin films grown on InSb have been plagued by heavy incorporation of the p-type dopant indium. To better study and make use of the topological phases in α-Sn, this indium doping must be minimized. The authors realize this reduction by tuning the surface reconstruction of InSb(001) on which molecular beam epitaxy growth of α-Sn is initiated. The low indium doping is verified by both photoemission and magnetotransport measurements. The accessibility of the surface Dirac node in angle-resolved photoemission spectroscopy—made possible by the substrate preparation procedure—allows direct measurements of the effect of confinement and epitaxial strain on the topological phase in this system.

This paper reports that domain-wall-like modes govern the magnetic response of the van der Waals material FeOCl. Due to boundaries, these excitations condense into an unconventional magnetic order with a diffusional dynamics as probed by Mössbauer spectroscopy and Raman scattering. These results have implications for a better understanding of fundamental aspects of soliton-like excitations as well as topological magnetism and related information storage. The authors highlight that the observed phenomenology and proposed condensation of solitons into topological edge states is a generic feature of non-linear systems with confinement.

While the efficacy of machine learning (ML) force fields in simulating molecular dynamics (MD) trajectories has already been well established, simulating Raman spectra from them requires polarizability models which are much less explored. In this work, three polarizability models are compared using three widely different materials, namely boron arsenide, 2D molybdenum disulfide and inorganic halide perovskites. The Raman spectra are obtained in combination with ML MD and compared to experiments, allowing us to highlight the advantages and shortcomings of each model.

The observation of Majorana anyons is a long-sought challenge in physics, but has been hindered by lack of high-quality materials. The authors fabricate a heterostructure with an atomically sharp interface between a quantum anomalous Hall insulator and superconductor, for the first time. This unique quantum material should enable the unambiguous observation of chiral Majorana edge states and braiding of non-Abelian anyons without magnetic field.

ABC miktoarm triblock terpolymer melts (or simply stars) are unique due to their tendency to self-assemble into nanostructures rarely found in other block copolymer systems, such as the various tiling patterns. Several discrepancies, however, exist among previous self-consistent field (SCF) calculations of symmetrically interacting stars, where the repulsion between different types of segments is the same. These are resolved with the authors’ high-accuracy SCF calculations that include all known tiling patterns, as well as several lamellar-type phases known to bound the regions occupied by the tiling patterns in the parameter space of block volume fractions $f$${}_P$ ($P$=A,B,C). Both the (3.4.6.4) tiling pattern and the 3D phase of hierarchical-hexagonal lamellae (HHL) are found to be stable for the first time, and their stability mechanisms including the important (3${}^2$.4.3.4) tiling pattern are revealed.

APS has selected 156 Outstanding Referees for 2024 who have demonstrated exceptional work in the assessment of manuscripts published in the Physical Review journals. A full list of the Outstanding Referees is available online.

Block copolymers provide both a model system for understanding symmetry breaking in soft matter and a unique platform for the design of nanostructured materials.

A discussion of the focus on materials related research in the Physical Review journals.