Skin-Inspired in-Sensor Encoding of Strain Vector Using Tunable Quantum Geometry

Human skin provides crucial tactile feedback, allowing to skillfully perceive various objects by sensing and encoding complex deformations through multiple parameters in each tactile receptor. However, replicating this high-dimensional tactile perception with conventional materials' electronic properties remains a daunting challenge. Here, a skin-inspired method is presented to encode strain vectors directly within a sensor. This is achieved by leveraging the strain-tunable quantum properties of electronic bands in the van der Waals topological semimetal Td-WTe2. Robust and independent responses are observed from the second-order and third-order nonlinear Hall signals in Td-WTe2 when subjected to variations in both the magnitude and direction of strain. Through rigorous temperature-dependent measurements and scaling law analysis, it is established that these strain responses primarily stem from quantum geometry-related phenomena, including the Berry curvature and Berry-connection polarizability tensor. Furthermore, the study demonstrates that strain-dependent nonlinear Hall signals can efficiently encode high-dimensional strain information using a single device. This capability enables accurate and comprehensive sensing of complex strain patterns in the embossed character "NJU". The findings highlight the promising application of topological quantum materials in advancing next-generation, bio-inspired flexible electronics.