Search for: All records

Twisted transition metal dichalcogenide (TMD) bilayers have enabled the discovery of superconductivity, ferromagnetism, correlated insulators, and a series of new topological phases of matter. However, the connection between these electronic phases of matter and the underlying band structure singularities has remained largely unexplored. Here, combining magnetic circular dichroism and exciton sensing measurements, we investigate the influence of a van Hove singularity (vHS) on the correlated phases in bilayer WSe₂with twist angle between 2 and 3 degrees. By tuning the vHS across the Fermi level using electric and magnetic fields, we observe Stoner ferromagnetism below moiré lattice filling one and Chern insulators at filling one. The experimental observations are supported by the continuum model band structure calculations. Our results highlight the prospect of engineering electronic phases of matter in moiré materials by tunable van Hove singularities.

Muscle loading is known to influence skeletal morphology. Therefore, modification of the biomechanical environment is expected to cause coordinated morphological changes to the bony and cartilaginous tissues. Understanding how this musculoskeletal coordination contributes to morphological variation has relevance to health sciences, developmental biology, and evolutionary biology. To investigate how muscle loading influences skeletal morphology, we replicate a classic in ovo embryology experiment in the domestic chick (Gallus gallus domesticus) while harnessing modern methodologies that allow us to quantify skeletal anatomy more precisely and in situ. We induced rigid muscle paralysis in developing chicks mid‐incubation, then compared the morphology of the cranium and mandible between immobilized and untreated embryos using microcomputed tomography and landmark‐based geometric morphometric methods. Like earlier studies, we found predictable differences in the size and shape of the cranium and mandible in paralyzed chicks. These differences were concentrated in areas known to experience high strains during feeding, including the jaw joint and jaw muscle attachment sites. These results highlight specific areas of the skull that appear to be mechanosensitive and suggest muscles that could produce the biomechanical stimuli necessary for normal hatchling morphology. Interestingly, these same areas correspond to areas that show the greatest disparity and fastest evolutionary rates across the avian diversity, which suggests that the musculoskeletal integration observed during development extends to macroevolutionary scales. Thus, selection and evolutionary changes to muscle physiology and architecture could generate large and predictable changes to skull morphology. Building upon previous work, the adoption of modern imaging and morphometric techniques allows richer characterization of musculoskeletal integration that empowers researchers to understand how tissue‐to‐tissue interactions contribute to overall phenotypic variation.