The density gradient model (DG) is tested for its ability to describe tunneling currents through thin insulating barriers. Simulations of single barriers (MOS diodes, MOSFETs) and double barriers show the limitations of the DG model. As a reference the Schrödinger-Bardeen method is taken. ‘Resonant tunneling’ in the density gradient model turns out to be an artifact related to large density dif...

We present the results of a detailed study of the thermally assisted-resonant-tunneling relaxation rate of Mn12 acetate as a function of an external, longitudinal magnetic field and find that the data can be fit extremely well to a Lorentzian function. No hint of inhomogeneous broadening is found, even though some is expected from the Mn nuclear hyperfine interaction. This inconsistency implies...

A single-mask lateral tunneling accelerometer with integrated tip has been developed and characterized. High aspect ratio single-crystal silicon springs provide high resolution, wide operating bandwidth, and excellent isolation from off-axis stimuli. In this paper, we present the first such device implementing the SCREAM [1] process technology. We focus on the advantages that this technology af...

We report the observation of resonant tunneling effects a t high applied fields in a multiple quantum-well P-I-N diode. The A10,81no,5,As/Gao,4,1no,53As structure shows features in the dark current due to Zener tunneling of electrons from the lowest sub-band in a valence-band quantum well to the first and second sub-bands of an adjacent conduction-band well.

Current steps attributed to resonant tunneling through individual InAs quantum dots embedded in a GaAs-AlAs-GaAs tunneling device are investigated experimentally in magnetic fields up to 28 T. The steps evolve into strongly enhanced current peaks in high fields. This can be understood as a fieldinduced Fermi-edge singularity due to the Coulomb interaction between the tunneling electron on the q...

We measure the high-frequency emission of a single Cooper pair transistor (SCPT) in the regime where transport is only due to tunneling of Cooper pairs. This is achieved by coupling on chip the SCPT to a superconductor-insulator-superconductor junction and by measuring the photon assisted tunneling current of quasiparticles across the junction. This technique allows a direct detection of the ac...

Following our recent interest in metamaterial-based devices supporting resonant tunneling, energy squeezing, and supercoupling through narrow waveguide channels and bends, here we analyze the fundamental physical mechanisms behind this phenomenon using a transmission-line model. These theoretical findings extend our theory, allowing us to take fully into account frequency dispersion and losses ...

The fastest tunneling response in double barrier resonant structures is investigated by considering explicit analytic solutions of the time dependent Schrödinger equation. For cutoff initial plane waves, we find that the earliest tunneling events consist on the emission of a series of propagating pulses of the probability density governed by the buildup oscillations in the quantum well. We show...

Zeeman splitting of the ground state of single impurities in the quantum well of a resonant tunneling heterostructure is reported. We determine the absolute magnitude of the effective magnetic spin splitting factor g ' for a single impurity in a 44 Å Al0.27Ga0.73AsyGaAsyAl0.27Ga0.73As quantum well to be 0.28 6 0.02. This system also allows for independent measurement of the electron tunneling r...

We have studied the polarized resolved photoluminescence in an n-type resonant tunneling diode (RTD) of GaAs/AlGaAs which incorporates a layer of InAs self-assembled quantum dots (QDs) in the center of a GaAs quantum well (QW). We have observed that the QD circular polarization degree depends on applied voltage and light intensity. Our results are explained in terms of the tunneling of minority...