Towards logic functions as the device

Abstract

This paper argues for alternate state variables and new types of sophisticated devices that implement more functionality in one computational step than typical devices based on simple switches. Elementary excitations in solids enabling wave interactions are possible initial candidates to create such new devices. The paper focuses on magnon-based spin-wave-logic functions (SPWF) and presents high fan-in majority, weighted high fan-in majority, and frequency-multiplexed weighted high fan-in majority devices as initial SPWFs. Experiments proving feasibility are also shown. Benefits vs. scaled CMOS are quantified. Results show that for 128 or larger inputs even a 2.5μm SPWF carry-look-ahead adder implementation is faster than the 45nm CMOS version. The 45nm SPWF adder is expected to be significantly faster across the whole range of input widths. In particular, the 45nm SPWF CLA adder is estimated to be at least 77X faster than CMOS version for input widths equal to or greater than 1024. A second example of a counter circuit is presented to illustrate the considerable reduction in complexity possible vs. CMOS.