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Register a new userTunable Negative Differential Resistance controlled by Spin Blockade in Single Electron Transistors
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We demonstrate a tunable negative differential resistance controlled by spin blockade in single electron transistors. The single electron transistors containing a few electrons and spin polarized source and drain contacts were formed in GaAs/GaAlAs heterojunctions using metallic gates. Coulomb blockade measurements performed as a function of applied source-drain bias, electron number and magnetic field reveal well defined regimes where a decrease in the current is observed with increasing bias. We establish that the origin of the negative differential regime is the spin-polarized detection of electrons combined with a long spin relaxation time in the dot. These results indicate new functionalities that may be utilized in nano-spintronic devices in which the spin state is electro-statically controlled via the electron occupation number.
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We show that Joule heating causes current-controlled negative differential resistance (CC-NDR) in TiO2 by constructing an analytical model of the voltage-current V(I) characteristic based on polaronic transport for Ohms Law and Newtons Law of Cooling, and fitting this model to experimental data. This threshold switching is the soft breakdown observed during electroforming of TiO2 and other transition-metal-oxide based memristors, as well as a precursor to ON or SET switching of unipolar memristors from their high to their low resistance states. The shape of the V(I) curve is a sensitive indicator of the nature of the polaronic conduction.
Nonlinear electrical properties, such as negative differential resistance (NDR), are essential in numerous electrical circuits, including memristors. Several physical origins have been proposed to lead to the NDR phenomena in semiconductor devices in the last more than half a century. Here, we report NDR behavior formation in randomly oriented graphene-like nanostructures up to 37 K and high on-current density up to 10^5 A/cm^2. Our modeling of the current-voltage characteristics, including the self-heating effects, suggests that strong temperature dependence of the low-bias resistance is responsible for the nonlinear electrical behavior. Our findings open opportunities for the practical realization of the on-demand NDR behavior in nanostructures of 2D and 3D material-based devices via heat management in the conducting films and the underlying substrates.
Effects of the spin-orbit interactions on the energy spectrum, Fermi surface and spin dynamics are studied in structural- and bulk-inversion asymmetric quasi-two-dimensional structures with a finite thickness in the presence of a parabolic transverse confining potential. One-particle quantum mechanical problem in the presence of an in-plane magnetic field is solved numerically exact. Interplay of the spin-orbit interactions, orbital- and Zeeman-effects of the in-plane magnetic field yields a multi-valley subband structure, typical for realization of the Gunn effect. A possible Gunn-effect-mediated spin accumulation is discussed.
We have observed tunable negative differential resistance (NDR) in scanning tunneling spectroscopy measurements of a double layer of C60 molecules on a metallic surface. Using a simple model we show that the observed NDR behavior is explained by voltage-dependent changes in the tunneling barrier height.
Single particle interference lies at the heart of quantum mechanics. The archetypal double-slit experiment has been repeated with electrons in vacuum up to the more massive $C_{60}$ molecules. Mesoscopic rings threaded by a magnetic flux provide the solid-state analogous. Intra-molecular interference has been recently discussed in molecular junctions. Here we propose to exploit interference to achieve all-electrical control of a single electron spin in quantum dots, a highly desirable property for spintronics and spin-qubit applications. The device consists of an interference single electron transistor (ISET), where destructive interference between orbitally degenerate electronic states produces current blocking at specific bias voltages. We show that in the presence of parallel polarized ferromagnetic leads the interplay between interference and the exchange coupling on the system generates an effective energy renormalization yielding different blocking biases for majority and minority spins. Hence, by tuning the bias voltage full control over the spin of the trapped electron is achieved.
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