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In a seminal paper now a decade old, it was shown that dark-matter detectors geared at probing interactions with nucleons could also be used to probe dark-matter interactions with electrons. In this Letter, we show that new detector concepts designed to probe dark-matter–electron interactions at low masses can similarly be used to probe new parameter space for dark-matter–nucleon interactions. We demonstrate the power of this approach by using existing data from superconducting detectors to place new limits on the interactions of nuclei with MeV-scale dark matter. Further, we show that advances in detector technology that have been anticipated for electronic interactions will automatically extend sensitivity deep into uncharted territory for nuclear interactions. This doubles the effective science output of future low-threshold experiments. 

1T–TaS2 is a layered charge density wave (CDW) crystal exhibiting sharp phase transitions and associated resistance changes. These resistance steps could be exploited for information storage, underscoring the importance of controlling and tuning the CDW states. Given the importance of out-of-plane interactions in 1T–TaS2, modulating interlayer interactions by heterostructuring is a promising method for tailoring CDW phase transitions. In this work, we investigate the optical and electronic properties of heterostructures comprising 1T–TaS2 and monolayer 1H–WSe2. By systematically varying the thickness of 1T–TaS2 and its azimuthal alignment with 1H–WSe2, we find that intrinsic moiré strain and interfacial charge transfer introduce CDW disorder in 1T–TaS2 and modify the CDW ordering temperature. Furthermore, our studies reveal that the interlayer alignment impacts the exciton dynamics in 1H–WSe2, indicating that heterostructuring can concurrently tailor the electronic phases in 1T–TaS2 and the optical properties of 1H–WSe2. This work presents a promising approach for engineering the optoelectronic behavior of heterostructures that integrate CDW materials and semiconductors. 

Abstract High-density phase change memory (PCM) storage is proposed for materials with multiple intermediate resistance states, which have been observed in 1T-TaS₂due to charge density wave (CDW) phase transitions. However, the metastability responsible for this behavior makes the presence of multistate switching unpredictable in TaS₂devices. Here, we demonstrate the fabrication of nanothick verti-lateralH-TaS₂/1T-TaS₂heterostructures in which the number of endotaxial metallicH-TaS₂monolayers dictates the number of resistance transitions in 1T-TaS₂lamellae near room temperature. Further, we also observe optically active heterochirality in the CDW superlattice structure, which is modulated in concert with the resistivity steps, and we show how strain engineering can be used to nucleate these polytype conversions. This work positions the principle of endotaxial heterostructures as a promising conceptual framework for reliable, non-volatile, and multi-level switching of structure, chirality, and resistance. 

Abstract Transition metal dichalcogenides (TMDs) offer superior properties over conventional materials in many areas such as in electronic devices. In recent years, TMDs have been shown to display a phase switching mechanism under the application of external mechanical strain, making them exciting candidates for phase change transistors. Molybdenum ditelluride (MoTe2) is one such material that has been engineered as a strain-based phase change transistor. In this work, we explore various aspects of the mechanical properties of this material by a suite of computational and experimental approaches. First, we present parameterization of an interatomic potential for modeling monolayer as well as multilayered MoTe2 films. For generating the empirical potential parameter set, we fit results from density functional theory calculations using a random search algorithm known as particle swarm optimization. The potential closely predicts structural properties, elastic constants, and vibrational frequencies of MoTe2 indicating a reliable fit. Our simulated mechanical response matches earlier larger scale experimental nanoindentation results with excellent prediction of fracture points. Simulation of uniaxial tensile deformation by molecular dynamics shows the complete non-linear stress-strain response up to failure. Mechanical behavior, including failure properties, exhibits directional anisotropy due to the variation of bond alignments with crystal orientation. Furthermore, we show the deterioration of mechanical properties with increasing temperature. Finally, we present computational and experimental evidence of an extended c-axis strain transfer length in MoTe2 compared to TMDs with smaller chalcogen atoms.