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Electric charge detection by atomic force microscopy (AFM) with single- electron resolution (e-EFM) is a promising way to investigate the electronic level structure of individual quantum dots (QD). The oscillating AFM tip modulates the…

Mesoscale and Nanoscale Physics · Physics 2017-01-10 Yoichi Miyahara , Antoine Roy-Gobeil , Peter Grutter

Single electron charging in an individual InAs quantum dot was observed by electrostatic force measurements with an atomic force microscope (AFM). The resonant frequency shift and the dissipated energy of an oscillating AFM cantilever were…

Images of a single-electron quantum dot were obtained in the Coulomb blockade regime at liquid He temperatures using a cooled scanning probe microscope (SPM). The charged SPM tip shifts the lowest energy level in the dot and creates a ring…

Using far-infrared spectroscopy, we investigate the excitations of self-organized InAs quantum dots as a function of the electron number per dot, 1<n<6, which is monitored in situ by capacitance spectroscopy. Whereas the well-known two-mode…

Condensed Matter · Physics 2009-10-28 M. Fricke , A. Lorke , J. P. Kotthaus , G. Medeiros-Ribeiro , P. M. Petroff

We demonstrate a novel method for measuring the discrete energy spectrum of a quantum dot connected very weakly to a single lead. A train of voltage pulses applied to a metal gate induces tunneling of electrons between the quantum dot and a…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 J. M. Elzerman , R. Hanson , L. H. Willems van Beveren , L. M. K. Vandersypen , L. P. Kouwenhoven

Electrostatic force microscopy at cryogenic temperatures was used to probe the electrostatic interaction between a conductive atomic force microscopy tip and electronic charges trapped in an InAs quantum dot. Measurement of the…

Condensed Matter · Physics 2016-08-16 Aykutlu Dâna , Charles Santori , Yoshihisa Yamamoto

We study the interplay between Coulomb blockade and the Kondo effect in quantum dots. We use a self-consistent scheme which describes mesoscopic devices in terms of a collective phase variable (slave rotor) and quasiparticle degrees of…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 S. Florens , P. San Jose , F. Guinea , A. Georges

The rate-equation approach is used to describe sequential tunneling through a molecular junction in the Coulomb blockade regime. Such device is composed of molecular quantum dot (with discrete energy levels) coupled with two metallic…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Kamil Walczak

Three terminal tunnelling experiments on quantum dots in the Coulomb blockade regime allow a quantitative determination of the coupling strength of individual quantum states to the leads. Exploiting this insight we have observed independent…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 R. Leturcq , D. Graf , T. Ihn , K. Ensslin , D. D. Driscoll , A. C. Gossard

A new theoretical method is introduced to study coherent electron transport in an interacting multilevel quantum dot. The method yields the correct behavior both in the limit of weak and strong coupling to the leads, giving a unified…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 A. Levy Yeyati , F. Flores , A. Martin-Rodero

We study the fluctuations of an energy level as a function of the number of electrons $m$ added to a Coulomb-blockade quantum dot. A microscopic calculation in the limit of Koopmans' theorem predicts that the standard deviation of these…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Y. Alhassid , Yuval Gefen

We consider electron systems in quantum dots and imaging of the confined charge density by the Coulomb blockade microscopy (CBM) with the scanning probe technique. We apply an exact diagonalization method to study the reaction of the…

Mesoscale and Nanoscale Physics · Physics 2014-06-27 E. Wach , D. P. Żebrowski , B. Szafran

Double-slit experiments inferring the phase and the amplitude of the transmission coefficient performed at quantum dots (QD), in the Coulomb blockade regime, present anomalies at the phase changes depending on the number of electrons…

Mesoscale and Nanoscale Physics · Physics 2013-05-21 A. I. Mese , A. Bilekkaya , S. Arslan , S. Aktas , A. Siddiki

We present Coulomb Blockade measurements of two few-electron quantum dots in series which are configured such that the electrochemical potential of one of the two dots is aligned with spin-selective leads. The charge transfer through the…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 M. Ciorga , M. Pioro-Ladrière , P. Zawadzki , J. Lapointe , Z. Wasilewski , A. S. Sachrajda

We study the electronic structure of a single self-assembled InAs quantum dot by probing elastic single-electron tunneling through a single pair of weakly coupled dots. In the region below pinch-off voltage, the non-linear threshold voltage…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 T. Ota , K. Ono , M. Stopa , T. Hatano , S. Tarucha , H. Z. Song , Y. Nakata , T. Miyazawa , T. Ohshima , N. Yokoyama

Two tunnel-coupled few-electron quantum dots were fabricated in a GaAs/AlGaAs quantum well. The absolute number of electrons in each dot could be determined from finite bias Coulomb blockade measurements and gate voltage scans of the dots,…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 I. H. Chan , P. Fallahi , A. Vidan , R. M. Westervelt , M. Hanson , A. C. Gossard

The spectral properties of up to four interacting electrons confined within a quasi one--dimensional system of finite length are determined by numerical diagonalization including the spin degree of freedom. The ground state energy is…

Condensed Matter · Physics 2009-10-22 Wolfgang Haeusler , Bernhard Kramer , PTB Braunschweig

We argue that Coulomb blockade phenomena are a useful probe of the cross-over to strong correlation in quantum dots. Through calculations at low density using variational and diffusion quantum Monte Carlo (up to r_s ~ 55), we find that the…

Mesoscale and Nanoscale Physics · Physics 2009-08-11 A. D. Guclu , A. Ghosal , C. J. Umrigar , H. U. Baranger

Sequential single-electron charging is observed in InAs Self-Assembled Quantum Dots using capacitance spectroscopy. In this system, the Coulomb energy is smaller than the inter-level energy spacings due to the quantum confinement and both…

Condensed Matter · Physics 2009-10-28 G. Medeiros-Ribeiro , F. G. Pikus , P. M. Petroff , A. L. Efros

We examine a quantum dot with $N_{\rm dot}$ levels which is strongly coupled to leads for varying number of channels $N$ in the leads. It is shown both analytically and numerically that for strong couplings between the dot and the leads, at…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Richard Berkovits , Felix von Oppen , Jan W. Kantelhardt
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