Stateful Logic Using Selector-Only-Memory With Tunable Operation Directionality.

The growing demand for energy- and area-efficient computing in edge devices has highlighted the limitations of conventional von Neumann architectures, which suffer from the memory bottleneck due to frequent data transfer between logic and memory units. Processing-in-memory (PIM) has emerged as a promising solution, and among its approaches, stateful logic enables computation directly within memory arrays using simple voltage pulses. To realize this concept, we demonstrate the stateful logic functionality using selector-only-memory (SOM) device based on Sn-doped GeSeTe (SGST). The device reveals a distinctive switching behavior, where the direction of threshold switching can be reversibly tuned by adjusting the external series resistance. This behavior originates from RC delay effects, which induce a residual opposite-polarity voltage during the falling edge of the input pulse. Utilizing this property, we implement various stateful logic operations-including IMPLY, NAND, NOR, AND, and OR-directly within the SOM array. Furthermore, a half-adder circuit is experimentally realized, confirming the scalability of the approach. The low off-state current and reconfigurable switching behavior make the SOM device highly suitable for dense and low-power logic-in-memory architectures, particularly in large-scale arrays for edge computing. This work will provide a new direction for designing stateful logic devices with both structural simplicity and functional versatility.