Cryogenic In-Memory Bit-Serial Addition Using Quantum Anomalous Hall Effect-Based Majority Logic

Cryogenic compute in- memory (CiM) is a promising alternative to room temperature von-Neumann technologies since cryogenic electronics can provide high speed and energy efficiency while CiM can solve the von-Neumann and memory wall bottlenecks. Moreover, CiM can reduce the energy requirement which can solve the cooling issues associated with the cryogenic systems. Here, we demonstrate a cryogenic in- memory full adder using Majority logic implemented in quantum anomalous Hall effect (QAHE)-based memory system. The utilization of QAHE-based memory enables a number of unique advantages for Majority logic– (i) Majority outputs correspond to voltages with two opposite polarities irrespective of the number of inputs and hence, only a simple voltage comparator can be used, (ii) in- memory Majority logic (and hence, full adder) does not require any modification in the peripheral circuitry, and (iii) the topologically protected Hall resistance states provide robustness against external variations. This work makes the first attempt to harness the unique advantages of QAHE phenomenon in implementing complex operations beyond the primitive bitwise Boolean operations.