Conductance

About: Conductance is a research topic. Over the lifetime, 8088 publications have been published within this topic receiving 235961 citations.

Multilevel conductance switching in organic memory devices based on AlQ3 and Al/Al2O3 core-shell nanoparticles

Abstract: Multilevel conductance switching in organic memory devices based on AlQ3 and Al/Al2O3 core-shell nanoparticles is demonstrated. The effect of middle Al layer thickness and the size of the nanoparticles on device performance are investigated. The high-resolution transmission electron micrographs revealed the formation of core-shell nanoparticles. The device has shown a series of conductance states. These states are nonvolatile in nature and can be accessed by applying proper programming voltage above a threshold voltage. Field-induced transfer of charge carriers between AlQ3 and aluminum core is proposed to be responsible for conductance switching.

Kondo conductance in an atomic nanocontact from first principles

Abstract: A route connecting density functional theory and the numerical renormalization group method represents the first approach to studying atomic contacts—including magnetic elements—at an atomic level. When applied to the case of a nickel impurity in a gold nanowire, the strategy provides a clear connection between the geometry and the transport properties. The electrical conductance of atomic metal contacts represents a powerful tool for detecting nanomagnetism. Conductance reflects magnetism through anomalies at zero bias1,2,3,4,5,6,7—generally with Fano line shapes—owing to the Kondo screening of the magnetic impurity bridging the contact8,9. A full atomic-level understanding of this nutshell many-body system is of the greatest importance, especially in view of our increasing need to control nanocurrents by means of magnetism. Disappointingly, at present, zero-bias conductance anomalies are not calculable from atomistic scratch. Here, we demonstrate a working route connecting approximately but quantitatively density functional theory (DFT) and numerical renormalization group (NRG) approaches and leading to a first-principles conductance calculation for a nanocontact, exemplified by a Ni impurity in a Au nanowire. A Fano-like conductance line shape is obtained microscopically, and shown to be controlled by the impurity s-level position. We also find a relationship between conductance anomaly and geometry, and uncover the possibility of opposite antiferromagnetic and ferromagnetic Kondo screening—the latter exhibiting a totally different and unexplored zero-bias anomaly. The present matching method between DFT and NRG should permit the quantitative understanding and exploration of this larger variety of Kondo phenomena at more general magnetic nanocontacts.

Logarithmic corrections to two-dimensional transport in silicon inversion layers

Abstract: It is shown that the logarithmic corrections to the two-dimensional conductance arise from both interaction and incipient localisation effects. A transition between these two type of behaviour can be achieved by a change of electron temperature in the presence of a magnetic field, or just by the application of a magnetic field. The magnetic field suppresses the weak localisation and enhances the effects of the interaction. Results on conductance, magnetoconductance and Hall effect are presented and discussed.

Characterization of large-conductance chloride channels in rabbit colonic smooth muscle.

Abstract: 1. A large-conductance Cl- channel was characterized in cell-free membrane patches from the rabbit longitudinal colonic smooth muscle using the patch clamp technique. In addition, the regulation of these channels by neurokinin-1 (NK-1) receptor agonists and G proteins was studied. 2. No spontaneous channel activity was observed in cell-attached patches at the cell resting potential, or in excised patches at pipette potentials (Vp) between -20 and 20 mV. In excised patches, channel activity could be induced in thirty-six out of ninety-six patches by holding the patch at Vp values more negative than -60 mV or more positive than 60 mV. Once induced, the channel showed a bell-shaped voltage activation curve in high symmetric [Cl-], with maximal open probability between 20 and -5 mV. Varying cytosolic calcium concentration ([Ca2+]) between 5 x 10(-8) M and 1.0 mM had no effect on the voltage activation of the channel. 3. In inside-out and outside-out patches, when pipette and bath solutions contained equal [Cl-] (130 mM), the anion channel showed a linear current-voltage (I-V) relationship between -60 and 60 mV with a slope conductance of 309 +/- 20 pS (n = 13). Reversal potential measurements indicated that the channel was selective for Cl- over Na+ and K+ (PCl/PNa = 6:1). 4. Channel openings from the closed state to the full open state as well as transitions through smaller conductance states were observed. The smallest detectable substate had a conductance of 15.6 pS. Based on the similarities in selectivity and linearity of the I-V curve of the smaller conductances with the full open state, and kinetic analysis of channel activity, it is concluded that the large conductance channel is composed of multiple substates which can either open and close independently, or simultaneously via a main gate. 5. The stilbene derivative diiso-thiocyanato-stilbene-disulphonic acid (DIDS) and the diphenylamine-2-carboxylate analogue 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) caused a dose-dependent, reversible flicker block of the small conductance and significantly reduced the macroscopic current flow through the channel. 6. In quiescent outside-out patches, when the pipette contained a 140 mM-CsCl solution with 10(-6) M-CaCl2, 1.2 mM-MgCl2 and 1 mM-GTP, and the bath contained Ringer solution, addition of the NK-1 receptor antagonists substance P methylester resulted in activation of the full conductance state and of smaller substates.(ABSTRACT TRUNCATED AT 400 WORDS)