  Future development of the modern nanoelectronics and its flagships internet
of things and artificial intelligence as well as many related applications is
largely associated with memristive elements. This technology offers a broad
spectrum of functionalities, however, it follows predominantly a
phenomenological approach and crucial challenge/limit for further development
remains variability and lack of fundamental materials' design strategy. Here we
demonstrate the vital importance of materials' purity for determining
memristors' functionalities, showing that part per million foreign elements
significantly change the performance. By appropriate choice of chemistry and
amount of doping material we can selectively enhance desired operation mode. We
highlight how dopant dependent structure and charge/potential distribution in
the space charge layers and the cell capacitance determine the device kinetics
and functions. We evidence for first time experimentally the relation between
materials properties and switching/neuromorphic performance, thus providing
rules and directions for a rational design of memristive devices.
