Here we provide an appraisal of the Poisson's ratios (υ) for natural elements, common oxides, silicate minerals, and rocks with the purpose of searching for naturally auxetic materials. The Poisson's ratios of equivalently isotropic polycrystalline aggregates were calculated from dynamically measured elastic properties. Alpha‐cristobalite is currently the only known naturally occurring mineral that has exclusively negative υ values at 20–1,500°C. Quartz and potentially berlinite (AlPO4) display auxetic behavior in the vicinity of their α‐β structure transition. None of the crystalline igneous and metamorphic rocks (e.g., amphibolite, gabbro, granite, peridotite, and schist) display auxetic behavior at pressures of >5 MPa and room temperature. Our experimental measurements showed that quartz‐rich sedimentary rocks (i.e., sandstone and siltstone) are most likely to be the only rocks with negative Poisson's ratios at low confining pressures (≤200 MPa) because their main constituent mineral, α‐quartz, already has extremely low Poisson's ratio (υ = 0.08) and they contain microcracks, micropores, and secondary minerals. This finding may provide a new explanation for formation of dome‐and‐basin structures in quartz‐rich sedimentary rocks in response to a horizontal compressional stress in the upper crust.

As the architecture of choice for future artificial-intelligent systems, the ideas of in-memory-and in-sensor-computing paradigms based on nonvon-Neumann architecture possess broad application prospects such as neuromorphic and sensor-memory-processor fusion systems. At the same time, these promising applications put diversified and strict requirements on the device performances, such as fast response to external signals, robust data security, and 3D integration potential. In this work, Au@VO 2 IR photodetectors and Ti/Au/VO 2 /Ti/Au threshold switching selectors are constructed, where the VO 2 thin films are realized by magnetron sputtering and water-vapor assisted post-annealing. Fast IR response is achieved in Au@ VO 2 photodetectors through a surface plasmon resonance-assisted metalinsulator transition. Furthermore, electroforming-free, tunable threshold voltage, steep switching slope, and selectivity of more than two orders of magnitude are observed in Ti/Au/VO 2 /Ti/Au threshold switching selector. Combining the functionalities of photodetection and selector, a VO 2 -based optical convolution engine demonstrates accurate and secure image-processing capability. These VO 2 -based devices are demonstrated as promising candidates for novel non-volatile memory, neuromorphic computing and sensor-memory-processor fusion applications.

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