Mottness of “Mott Memristors” Required for Neuromorphic Computing
Prof. Louis Piper
The evolution of classical computing, often predicted by the Moore’s Law, where the number of
transistors integrated into a circuit is expected to double every two years is expected to reach
theoretical limits in terms of the size of the transistors. Among the methods currently being
developed to counter this limit of computational power is what is known as ‘NeuromorphicComputing’ (NM). This method tries to combine the processing of logic and memory, which has
classically been dealt as two separate steps which is akin to how the human brain functions where
it possesses supercomputing class performance with energy consumption levels around 20W
using ‘neuristors’. The existence of a ‘memristor’ capable of simultaneous processing of logic and
memory, was proposed back in 1971, whereas the experimental proof eluded scientists till 2006.
This feat has been demonstrated to be a possibility albeit with some debate as to the actual
definition of a memristor cropping up years later. This memristor had TiO 2 sandwiched between
Pt contacts. Such capability has also been researched using NbO2 which requires crystallite
formation using electroforming within a disordered NbOx setup. The switching mechanisms in the
preliminary memristors involved breaking and forming of conductive filaments. However, this is
prohibitive in both scaling as well as practical implementation. However, the scaling and difficulty
in commercial production has made it unattractive for wider implementations yet. This study
focuses on utilizing the metal insulator transition seen in Mott memristors to develop an energy
efficient neuristor. Phases which can co-exist are explored in NbO2, VO2, V2O3 based memristors
using defect-controlled transport. Additionally, XPS and HAXPES has been used to confirm that
the oxygen concentration and the rectification is inversely related.