Digital computing is nearing its physical limits as computing needs and energy consumption rapidly increase. Analogue‐memory‐based neuromorphic computing can be orders of magnitude more energy efficient at data‐intensive tasks like deep neural networks, but has been limited by the inaccurate and unpredictable switching of analogue resistive memory. Filamentary resistive random access memory (RRAM) suffers from stochastic switching due to the random kinetic motion of discrete defects in the nanometer‐sized filament. In this work, this stochasticity is overcome by incorporating a solid electrolyte interlayer, in this case, yttria‐stabilized zirconia (YSZ), toward eliminating filaments. Filament‐free, bulk‐RRAM cells instead store analogue states using the bulk point defect concentration, yielding predictable switching because the statistical ensemble behavior of oxygen vacancy defects is deterministic even when individual defects are stochastic. Both experiments and modeling show bulk‐RRAM devices using TiO2‐X switching layers and YSZ electrolytes yield deterministic and linear analogue switching for efficient inference and training. Bulk‐RRAM solves many outstanding issues with memristor unpredictability that have inhibited commercialization, and can, therefore, enable unprecedented new applications for energy‐efficient neuromorphic computing. Beyond RRAM, this work shows how harnessing bulk point defects in ionic materials can be used to engineer deterministic nanoelectronic materials and devices.

This structure disappears with increasing electron temperature and is ascribed to weak n*2 satellites, such as a_, and to n = 3 satellites, respectively. Table I Experimental and theoretical wavelengths are listed in ACKNOWLEDGMENTS

The usual predictions of linear coupling theory for lower hybrid waves are altered by including an overdense edge plasma (ω < ωpe) in the plasma model. Coupling is found to depend strongly on the value of the edge density, as well as the density gradient. The regimes, where one or the other of these parameters is important, are investigated. Typically, only the first few millimetres of the edge plasma are important in determining coupling. The major implications of the problem of coupling to an overdense plasma can be derived from a simple impedance-matching argument. In general, coupling is optimum for an edge density, n0, determined by , where nc = ω2me/4πe2 and n‖ is the parallel index of refraction of the lower hybrid wave.