Ternary In-Memory Computing with Cryogenic Quantum Anomalous Hall Effect Memories

With surging interest in quantum computing, space applications, and ultra-fast superconducting processors, the need for compatible cryogenic memory systems is skyrocketing. Among several concurrent candidates for cryogenic data storage solutions, quantum anomalous Hall effect (QAHE) devices have garnered immense interest due to having topologically protected variation-tolerant quantum states. QAHE cells, in addition to being a promising nonvolatile storage technology, have several unique properties that make them ideal for in-memory computing operations. In this work, we propose a novel in-memory computing mechanism by harnessing the intrinsic voltage addition property of a QAHE memory array, implemented using twisted bi-layer graphene (tBLG) on hexagonal boron nitride (hBN). In addition, we extensively explore and implement ternary arithmetic operations utilizing the series-connected Hall voltages across devices for the first time. We propose two schemes for in-memory ternary computing namely IMFE and IMSE, and demonstrate balanced scalar multiplication, dot product operations, and ternary half adder with QAHE memory array.