Quantum Anomalous Hall Effect Ternary Content Addressable Memory

Madison Ashbach, Md. Mazharul Islam, Shamiul Alam, Ahmedullah Aziz, Sumitha George

Abstract: As CMOS scaling approaches its physical limitations, exploring low-power alternative computing paradigms like cryogenic computing becomes crucial. A recently introduced cryogenic device utilizing twisted bilayer graphene (tBLG) on hexagonal boron nitride (hBN), offers a scalable solution for cryogenic memory. This device leverages the quantum anomalous Hall effect (QAHE) to manifest two topologically-protected, variation-tolerant non-volatile resistive states. The memory states are discerned by the direction of the Hall voltage across the device's terminals. In this work, we present a novel Ternary Content Addressable Memory (TCAM) design incorporating QAHE devices for the first time. Compared to the previous QAHE based Binary CAM design [1], our proposed TCAM design obviates the need for complex sense amplifiers by generating zero voltage on the match line output in the event of a perfect match. We also demonstrate that CAM functionality can be seamlessly integrated without altering the memory array hardware. We verify the design and functionality through SPICE simulations. Through a comprehensive 500-point Monte Carlo variation analysis, we validate the reliability of our proposed CAM design, even under worst-case variations, thereby establishing its robustness against variations.