Electron-electron interactions in nano-patterned La 0.3 Sr 0.7 MnO 3 thin films

International audienceUnderstanding the transport in ultra-thin epitaxial La0.3Sr0.7MnO3 (LSMO) is a topic widespread current interest. Here we explore electron-electron interactions in low temperature magneto-transport in straight and zigzag nanowires fabricated from ultra-thin epitaxial LSMO films grown to different thicknesses on STO(100) substrates. We find that three-dimensional electron-electron interactions can explain the resistivity upturn, including many of the changes observed with film thickness, nano-patterning, and magnetic field

Invited - Spiking neuron circuits in ULSIC vs TFT technologies

Recent advances on computing systems have enabled increasing success of algorithms using artificial intelligence. Researchers are now exploring new computational paradigms and materials to enable computing at the level of the device, allowing increased privacy and also reduction in energy. One of the most promising techniques is to realize circuits that imitate how neurons in biological brains function. Spike-based neural networks have been shown to hold more computational power than other neuromorphic architectures and their integration into mainstream computing is projected to herald a new age of computational power. Integrating neuron circuits with the functionality of materials used in flexible electronics is likely to open up a large field of applications, most notably for sensors for continuous health monitoring. In traditional MOFET technologies, spiking neuron circuits are typically operated in the deep subthreshold in order to take advantage of the exponential dependence of Vg to achieve the spiking action and also to optimize energy consumption. Nevertheless, this gives rise to some challenging problems when implemented in flexible technologies where the desire for using low cost and low temperature processes leads to lower mobility and much greater variability in device processing. Please click Download on the upper right corner to see the full abstract

Multi-island single-electron devices from self-assembled colloidal nanocrystal chains

We report the fabrication of multi-island single-electron devices made by lithographic contacting of self-assembled alkanethiol-coated gold nanocrystals. The advantages of this method, which bridges the dimensional gap between lithographic and NC sizes, are (1) that all tunnel junctions are defined by self-assembly rather than lithography and (2) that the ratio of gate capacitance to total capacitance is high. The rich electronic behavior of a double-island device, measured at 4.2 K, is predicted in detail by combining finite element and Monte Carlo simulations with the standard theory of Coulomb blockade with very few adjustable parameters.Comment: 4 page

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements