Possible cooling by resonant Fowler-Nordheim emission

A new method of electronic refrigeration based on resonant Fowler-Nordheim emission is proposed and analyzed. In this method, a bulk emitter is covered with a-few-nm-thick film of a widegap semiconductor, creating an intermediate step between electron energies in the emitter and in vacuum. An external electric field tilts this potential profile, forming a quantum well, and hence 2D electron subbands at the semiconductor-vacuum boundary. Alignment of the lowest subband with the energy levels of the hottest electrons of the emitter (a few $k_{B}T$ above its Fermi level) leads to a resonant, selective emission of these electrons, providing emitter cooling. Calculations show that cooling power as high as 10^{4} W/cm^{2} (at 300 K), and temperatures down to 10 K may be achieved using this effect.Comment: 4 pages, 2 figure

Single-Electron Parametron: Reversible Computation in a Discrete State System

We have analyzed energy dissipation in a digital device (``Single-Electron Parametron'') in which discrete degrees of freedom are used for presenting digital information. If the switching speed is not too high, the device may operate reversibly (adiabatically), and the energy dissipation ${\cal E}$ per bit may be much less than the thermal energy $k_BT$. The energy-time product ${\cal E}\tau$ is, however, much larger than Planck's constant $\hbar$, at least in the standard ``orthodox'' model of single-electron tunneling, which was used in our calculations.Comment: 9 pages, RevTex, 3 figure

Capacity, Fidelity, and Noise Tolerance of Associative Spatial-Temporal Memories Based on Memristive Neuromorphic Network

We have calculated the key characteristics of associative (content-addressable) spatial-temporal memories based on neuromorphic networks with restricted connectivity - "CrossNets". Such networks may be naturally implemented in nanoelectronic hardware using hybrid CMOS/memristor circuits, which may feature extremely high energy efficiency, approaching that of biological cortical circuits, at much higher operation speed. Our numerical simulations, in some cases confirmed by analytical calculations, have shown that the characteristics depend substantially on the method of information recording into the memory. Of the four methods we have explored, two look especially promising - one based on the quadratic programming, and the other one being a specific discrete version of the gradient descent. The latter method provides a slightly lower memory capacity (at the same fidelity) then the former one, but it allows local recording, which may be more readily implemented in nanoelectronic hardware. Most importantly, at the synchronous retrieval, both methods provide a capacity higher than that of the well-known Ternary Content-Addressable Memories with the same number of nonvolatile memory cells (e.g., memristors), though the input noise immunity of the CrossNet memories is somewhat lower

Shot noise in frustrated single-electron arrays

We have carried out numerical simulations of shot noise in 2D arrays of single-electron islands with random background charges. The results show that in contrast with the 1D arrays, at low currents the current noise is strongly colored, and its spectral density levels off at very low frequencies. The Fano factor may be much larger than unity, due to the remnants of single-electron/hole avalanches. However, even very small thermal fluctuations reduce the Fano factor below 1 for almost any bias.Comment: 3 pages, 4 figure

Quantum Fluctuations in Josephson Junction Comparators

We have developed a method for calculation of quantum fluctuation effects, in particular of the uncertainty zone developing at the potential curvature sign inversion, for a damped harmonic oscillator with arbitrary time dependence of frequency and for arbitrary temperature, within the Caldeira-Leggett model. The method has been applied to the calculation of the gray zone width Delta Ix of Josephson-junction balanced comparators driven by a specially designed low-impedance RSFQ circuit. The calculated temperature dependence of Delta Ix in the range 1.5 to 4.2K is in a virtually perfect agreement with experimental data for Nb-trilayer comparators with critical current densities of 1.0 and 5.5 kA/cm^2, without any fitting parameters.Comment: 4 pages, 4 figures, submitted to Physical Review Letter