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Search Publications by: Mark Keller (Fed)

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Displaying 26 - 50 of 50

Single-electron transistor spectroscopy of InGaAs self-assembled quantum dots

March 1, 2004
Author(s)
Kevin Osborn, Mark W. Keller, Richard Mirin
A single-electron transistor (SET) is used to detect tunneling of single electrons into individual InGaAs self-assembled quantum dots (QDs). By using an SET with a small island area and growing QDs with a low density we are able to distinguish and measure

Nonequilibrium Quasiparticles and Periodicity in Single-Cooper-Pair Transistors

February 13, 2004
Author(s)
Joe Aumentado, Mark W. Keller, John M. Martinis, Michel H. Devoret
We have made single-Cooper-pair transistors in which we control the spatial profile of the superconducting gap energy by oxygen doping. The profile dramatically affects the switching current vs. gate voltage curve of the transistor, changing its period

Single-Electron Transistor Spectroscopy of InGaAs Self-Assembled Quantum Dots

January 1, 2004
Author(s)
Kevin Osborn, Mark W. Keller, Richard Mirin
A single-electron transistor is used to detect tunneling of single electrons into self-assembled InGaAs quantum dots. Aluminum single-electron transistors (SETs) are fabricated over an MBE-grown structure containing quantum dots (QDs) and an underlying n

Electrical metrology with single electrons

July 16, 2003
Author(s)
Neil M. Zimmerman, Mark W. Keller
This paper is mostly a review of the progress made at NIST in pursuing a capacitance standard based on the charge of the electron. We briefly introduce the Coulomb blockade, which is the basic physical phenomenon allowing control of single electrons

Counting Errors in a Voltage-Biased Electron Pump

April 30, 2003
Author(s)
Xavier Jehl, Mark W. Keller, Richard L. Kautz, Joe Aumentado, John M. Martinis
We have measured the counting errors of a 7-junction electron pump when charge is pumped against a voltage difference. At voltages above about 50 υV, we find that the errors increase exponentially with both pump voltage and temperature, in agreement with

A Seven Junction Cooper Pair Pump

February 15, 2003
Author(s)
Joe Aumentado, Mark W. Keller, John M. Martinis
We have measured current-voltage curves and individual charge transfer events in single-Cooper-pair pumps. We observe clear charge pumping in units of 2e, but this behavior is accompanied by significant effects from unwanted quasiparticles.

Single-Cooper-Pair Transistors: Requirements for Robust 2e Periodicity

January 3, 2003
Author(s)
Joe Aumentado, Mark W. Keller, John M. Martinis
The superconducting analog of the single-electron transistor (SET), the single-Cooper-pair transistor (SCPT), is comprised of two ultrasmall tunnel junctions in series forming an island (see Figure 1(a)). Transport through the SCPT depends on the

Bimodal Size Distribution of Self-Assembled InGaAs Quantum Dots

September 23, 2002
Author(s)
Solveig Anders, C. S. Kim, Benjamin D. Klein, Mark W. Keller, Richard Mirin
We investigate energy level quantization in self-assembled InGaAs quantum dots that are embedded In a GaAs matrix. We use capacitance and photoluminescence spectroscopy to analyze the evolution of the energy levels with varying amounts of deposited InGaAs

Noise-Induced Leakage and Counting Errors in the Electron Pump

December 15, 2000
Author(s)
Richard L. Kautz, Mark W. Keller, John M. Martinis
Computer simulations reveal that the lowest rates of leakage and counting errors observed in the electron pump can be explained by photon-assisted tunneling driven by 1/f noise. The noise power at microwave frequencies required to account for the observed

Photon-Assisted Tunneling in Electron Pumps

May 29, 2000
Author(s)
M. Covington, Mark W. Keller, Richard L. Kautz, John M. Martinis
We measure photon-assisted tunneling in 4- and 6-junction electron pumps at photon frequencies up to 60 GHz. We determine the microwave voltage at the pumps using noise thermometry. The standard theory of leakage in the electron pump, modified to include

A Capacitance Standard Based on Counting Electrons: Progress Report

May 1, 2000
Author(s)
Mark W. Keller, Neil M. Zimmerman, Ali L. Eichenberger, John M. Martinis
We have built a prototype capacitance standard based on single-electron tunneling (SET) devices and a cryogenic vacuum-gap capacitor. We are currently involved in a thorough uncertainty analysis of the prototype, and we are preparing to make a direct

A Capacitance Standard Based on Counting Electrons

September 10, 1999
Author(s)
Mark W. Keller, Ali L. Eichenberger, John M. Martinis, Neil M. Zimmerman
A capacitance standard based directly on the definition of capacitance was built. Single-electron tunneling devices were used to place N electrons of charge e onto a cryogenic capacitor C, and the resulting voltage change ΔV was measured. Repeated

Leakage and Counting Errors in a Seven-junction Electron Pump

September 1, 1999
Author(s)
Richard L. Kautz, Mark W. Keller, John M. Martinis
Leakage and counting errors are explored experimentally in a well-characterized seven-junction electron pump and compared with predictions of the orthodox theory, including cotunneling.