Controlling quantum transport through a single molecule

We investigate multi-terminal quantum transport through single monocyclic aromatic annulene molecules, and their derivatives, using the nonequilibrium Green function approach in the self-consistent Hartree-Fock approximation. A new device concept, the Quantum Interference Effect Transistor (QuIET) is proposed, exploiting perfect destructive interference stemming from molecular symmetry, and controlling current flow by introducing decoherence and/or elastic scattering that break the symmetry. This approach overcomes the fundamental problems of power dissipation and environmental sensitivity that beset many nanoscale device proposals.Comment: 4 pages, 5 figure

Oscillating magnetoresistance due to fragile spin structure in metallic GdPd3_3

Studies on the phenomenon of magnetoresistance (MR) have produced intriguing and application-oriented outcomes for decades--colossal MR, giant MR and recently discovered extremely large MR of millions of percents in semimetals can be taken as examples. We report here the investigation of oscillating MR in a cubic intermetallic compound GdPd$_3$, which is the only compound that exhibits MR oscillations between positive and negative values. Our study shows that a very strong correlation between magnetic, electrical and magnetotransport properties is present in this compound. The magnetic structure in GdPd$_3$ is highly fragile since applied magnetic fields of moderate strength significantly alter the spin arrangement within the system--a behavior that manifests itself in the oscillating MR. Intriguing magnetotransport characteristics of GdPd$_3$ are appealing for field-sensitive device applications, especially if the MR oscillation could materialize at higher temperature by manipulating the magnetic interaction through perturbations caused by chemical substitutions.Comment: 10 pages, 7 figures. A slightly modified version is published in Scientific Report

XVII. On the Bhattikavya

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Towards Scalable Visual Exploration of Very Large RDF Graphs

In this paper, we outline our work on developing a disk-based infrastructure for efficient visualization and graph exploration operations over very large graphs. The proposed platform, called graphVizdb, is based on a novel technique for indexing and storing the graph. Particularly, the graph layout is indexed with a spatial data structure, i.e., an R-tree, and stored in a database. In runtime, user operations are translated into efficient spatial operations (i.e., window queries) in the backend.Comment: 12th Extended Semantic Web Conference (ESWC 2015