LAUSR

Modulating semiconducting channel potential has been used for electrical switching in transistors without biological plasticity operations that are critical for energy‐efficient neuromorphic computing. To achieve efficient data processing, alternative transport mechanisms, such as tunneling and thermionic emission, have been introduced with 2D materials. Here, a polymorphic memtransistor based on atomically thin Mo0.91W0.09Te2 is presented, where the lattice and electronic structures of the lateral device channel can be tuned as either metallic (1T′) or semiconducting (2H) phases by electrical gating. The structural and electronic phase change of the channel material, optimized in Mo0.91W0.09Te2, is explored using transport and optical measurements at the device scale. Based on the phase transition, the polymorphic memtransistor demonstrates a high on/off ratio (up to 105), low subthreshold swing (down to 80 mV dec−1), and various memristive behaviors, which are distinguished from traditional phase‐change memory, transistors, and passive memristors for diverse neuromorphic and in‐memory computing.