Single Electron Tunneling
Abstract
Financial support for this project has led to advances in the science of single-electron phenomena. Our group reported the first observation of the so-called ''Coulomb Staircase'', which was produced by tunneling into ultra-small metal particles. This work showed well-defined tunneling voltage steps of width e/C and height e/RC, demonstrating tunneling quantized on the single-electron level. This work was published in a now well-cited Physical Review Letter. Single-electron physics is now a major sub-field of condensed-matter physics, and fundamental work in the area continues to be conducted by tunneling in ultra-small metal particles. In addition, there are now single-electron transistors that add a controlling gate to modulate the charge on ultra-small photolithographically defined capacitive elements. Single-electron transistors are now at the heart of at least one experimental quantum-computer element, and single-electron transistor pumps may soon be used to define fundamental quantities such as the farad (capacitance) and the ampere (current). Novel computer technology based on single-electron quantum dots is also being developed. In related work, our group played the leading role in the explanation of experimental results observed during the initial phases of tunneling experiments with the high-temperature superconductors. When so-called ''multiple-gap'' tunneling was reported, the phenomenon was correctly identified bymore »
- Authors:
- Publication Date:
- Research Org.:
- University of Notre Dame
- Sponsoring Org.:
- USDOE - Office of Energy Research (ER)
- OSTI Identifier:
- 899023
- Report Number(s):
- DOE/ER/45373
TRN: US0702181
- DOE Contract Number:
- FG02-88ER45373
- Resource Type:
- Technical Report
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; TUNNEL EFFECT; ELECTRONS; METALS; CAPACITANCE; QUANTUM DOTS; SCANNING TUNNELING MICROSCOPY; SUPERCONDUCTORS; TRANSISTORS
Citation Formats
Ruggiero, Steven T. Single Electron Tunneling. United States: N. p., 2005.
Web. doi:10.2172/899023.
Ruggiero, Steven T. Single Electron Tunneling. United States. doi:10.2172/899023.
Ruggiero, Steven T. Mon .
"Single Electron Tunneling". United States.
doi:10.2172/899023. https://www.osti.gov/servlets/purl/899023.
@article{osti_899023,
title = {Single Electron Tunneling},
author = {Ruggiero, Steven T.},
abstractNote = {Financial support for this project has led to advances in the science of single-electron phenomena. Our group reported the first observation of the so-called ''Coulomb Staircase'', which was produced by tunneling into ultra-small metal particles. This work showed well-defined tunneling voltage steps of width e/C and height e/RC, demonstrating tunneling quantized on the single-electron level. This work was published in a now well-cited Physical Review Letter. Single-electron physics is now a major sub-field of condensed-matter physics, and fundamental work in the area continues to be conducted by tunneling in ultra-small metal particles. In addition, there are now single-electron transistors that add a controlling gate to modulate the charge on ultra-small photolithographically defined capacitive elements. Single-electron transistors are now at the heart of at least one experimental quantum-computer element, and single-electron transistor pumps may soon be used to define fundamental quantities such as the farad (capacitance) and the ampere (current). Novel computer technology based on single-electron quantum dots is also being developed. In related work, our group played the leading role in the explanation of experimental results observed during the initial phases of tunneling experiments with the high-temperature superconductors. When so-called ''multiple-gap'' tunneling was reported, the phenomenon was correctly identified by our group as single-electron tunneling in small grains in the material. The main focus throughout this project has been to explore single electron phenomena both in traditional tunneling formats of the type metal/insulator/particles/insulator/metal and using scanning tunneling microscopy to probe few-particle systems. This has been done under varying conditions of temperature, applied magnetic field, and with different materials systems. These have included metals, semi-metals, and superconductors. Amongst a number of results, we have verified that clusters of down to one, two, and three metal atoms can be identified with single-electron techniques. We have also, extended the regime of single-electron phenomenology through the observation of single-electron effects in metal droplets in the high-conductance regime.},
doi = {10.2172/899023},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jul 25 00:00:00 EDT 2005},
month = {Mon Jul 25 00:00:00 EDT 2005}
}
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Pictures using the low-temperature microwave scanning tunneling microscope, have been made of particles and tunneling IV characteristics determined. Strong, sometimes periodic negative differential resistance was observed in small-particle systems. Au and Ag droplets and particles were studied. 4 figs.
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Single-electron and oxide-impurity effects in junctions formed by a cryogenic scanning tunneling microscope
The authors show that the I-V characteristics measured at 4 K of single tunnel junctions between the tip of a scanning tunneling microscope and a metallic sample are sensitive to the materials used. The superconducting energy gap of lead is observed for tips without surface oxides, but eliminated for tips with thick oxides. Probing bulk etched tungsten, observation of the Coulomb staircase suggests capacitive effects due to a small metallic-oxide impurity. -
Single-electron tunneling. Technical progress report
Pictures using the low-temperature microwave scanning tunneling microscope, have been made of particles and tunneling IV characteristics determined. Strong, sometimes periodic negative differential resistance was observed in small-particle systems. Au and Ag droplets and particles were studied. 4 figs. -
Surface structure and analysis with scanning tunneling microscopy and electron tunneling spectroscopy: Progress report, May 1, 1986-April 30, 1987
The discussion includes a list of publications, talks and theses, the design and fabrication of the microscope, charge-density wave studies with scanning tunneling microscopes at 77 and 4.23 K, and data acquisition and graphics display systems. 3 figs. -
Surface structure and analysis with scanning tunneling microscopy and electron tunneling spectroscopy
During the current grant period we have continued to develop the spectroscopic applications of the Scanning Tunneling Microscopy and have carried out a large number of measurements on the gap structure due to charge-density waves and superconductivity. The measured energy gaps in 2H-TaSe{sub 2}, 2H-TaS{sub 2} and 2H-NbSe{sub 2} are {Delta} = 80, 50, and 34 mV giving values of 2{Delta}/k{sub B}T{sub c} of 15.2, 15.4 and 21.9. Measured energy gaps in 1T-TaSe{sub 2} and 1T- TaS{sub 2} are {Delta} {approx equal} 150 mV with 2{Delta}/k{sub B}T{sub c} {approx equal} 5.8. In the linear chain compounds, initial measurements have determinedmore »