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Search Publications by: David B. Newell (Fed)

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Displaying 101 - 125 of 167

Pseudomagnetic Fields in a Locally Strained Graphene Drumhead

August 25, 2014
Author(s)
Shuze Zhu, Yinjun Huang, Nikolai Klimov, David B. Newell, Nikolai Zhitenev, Joseph A. Stroscio, Santiago D. Solares Rivera, Teng Li
Recent experiments reveal that a scanning tunneling microscopy (STM) probe tip can generate a highly localized strain field in a graphene drumhead, which in turn leads to pseudomagnetic fields in the graphene that can spatially confine graphene charge

Heterodyne interferometer with subnanometer accuracy

August 24, 2014
Author(s)
Darine El Haddad, Frank C. Seifert, Stephan Schlamminger, Leon S. Chao, David B. Newell, Jon R. Pratt
This paper gives a brief description of the laser interferometer system designed for the next generation watt balance experiment aimed to realize the unit of mass by direct link to Planck constant at the National Institute of Standards and Technology. The

The Design of the NEW NIST-4 Watt Balance

August 24, 2014
Author(s)
Leon S. Chao, Stephan Schlamminger, Frank C. Seifert, Yusi A. Cao, Darine El Haddad, David B. Newell, Jon R. Pratt
The design of the new permanent-magnet driven watt balance and novel mechanical features will demonstrate the high-precision capabilities of a large complex mass measurement system with expected overall uncertainties on the order of 3 parts in 10^8.

The Measurement of the Local Acceleration of Gravity for the NIST4 Watt Balance

August 24, 2014
Author(s)
David B. Newell, Jacques Liard, Leon S. Chao, Yusi A. Cao, Frank C. Seifert, Darine El Haddad, Jon R. Pratt, Stephan Schlamminger
A new watt balance is being constructed at NIST in preparation for the redefinition of the International System of Units and the realization of mass through an exact value of the Planck constant. We describe the procedures used and give results for the

Construction of a watt balance with the aim to realize the kilogram at the National Institute of Standards and Technology

August 1, 2014
Author(s)
Darine El Haddad, Leon Chao, Frank Seifert, David B. Newell, Jon R. Pratt, Stephan Schlamminger
A redefinition of the International System of Units, the SI, is impending and could occur as early as 2017. After redefinition a means to realize the unit of mass is required. A watt balance is a promising device to realize the unit of mass at the kilogram

Development of Low Carrier Density Graphene Devices

August 1, 2014
Author(s)
Yanfei Yang, Lung-I Huang, David B. Newell, Yasuhiro Fukuyama, Mariano A. Real, Randolph Elmquist
Epitaxial graphene on SiC(0001) is used to fabricate Hall bar structures for metrological applications with a fabrication process that has been developed to eliminate organic chemical contamination of the graphene. Before any lithographic patterning a

Determination of the Planck constant at the National Institute of Standards and Technology

July 1, 2014
Author(s)
Stephan Schlamminger, Darine El Haddad, Frank C. Seifert, Leon S. Chao, David B. Newell, Ruimin Liu, Richard L. Steiner, Jon R. Pratt
In 2013, a new measurement of the Planck constant h was performed using a watt balance at the National Institute of Standards and Technology (NIST). The value is h=6.626 069 79(30) x 10^{-34} J s. The relative standard uncertainty of this determination is

Low carrier density epitaxial graphene devices on SiC

June 1, 2014
Author(s)
Yanfei Yang, Lung-I Huang, Yasuhiro Fukuyama, Fan-Hung Liu, Mariano Real, Paola Barbara, Chi-Te Liang, David B. Newell, Randolph Elmquist
Monolayer epitaxial graphene grown on a hexagonal silicon carbide (SiC) substrate is typically found to be heavily n-doped (10e13 cm-2) and in most devices made with the as-grown epitaxial graphene the quantized Hall resistance plateau with Landau level

Determination of the Planck constant using a watt balance with a superconducting magnet system at the National Institute of Standards and Technology

March 31, 2014
Author(s)
Stephan Schlamminger, Darine El Haddad, Frank C. Seifert, Leon S. Chao, David B. Newell, Richard L. Steiner, Jon R. Pratt
In the past two years measurements were performed with a watt balance at the National Institute of Standards and Technology (NIST) to determine the Planck constant. A detailed analysis of these measurements and their uncertainties led to a value of h=6.626

Graphene Epitaxial Growth on SiC(0001) for Resistance Standards

June 3, 2013
Author(s)
Mariano A. Real, Eric Lass, Fan-Hung H. Liu, Tian T. Shen, George R. Jones Jr., Johannes A. Soons, David B. Newell, Albert Davydov, Randolph Elmquist
A well-controlled technique for high-temperature epitaxial growth on 6H-SiC(0001) substrates is shown to allow development of monolayer graphene that exhibits promise for precise metrological applications. Face-to-face (FTF) and face-to-graphite (FTG)

The Planck constant, watt and vacuum balances, and an evolving Mise en pratique for the kilogram in North America

July 1, 2012
Author(s)
Jon R. Pratt, David B. Newell, Zeina J. Kubarych, Stephan Schlamminger, Darine El Haddad, Ruimin Liu, Edwin R. Williams, Dave Inglis, Barry M. Wood, Carlos Sanchez, Richard Green
We report preparations underway at the National Institute of Standards and Technology (NIST) in the United States and at the National Research Council (NRC) in Canada to support the redefinition of the international system of units (SI) and the development

Electro-Mechanical Properties of Graphene Drumheads

June 22, 2012
Author(s)
Nikolai N. Klimov, Suyong S. Jung, Shuze Zhu, Teng Li, C. Alan Wright, Santiago Solares, David B. Newell, Nikolai B. Zhitenev, Joseph A. Stroscio
The electro-mechanical properties of a suspended graphene layer are determined by scanning tunneling microscopy (STM) and spectroscopy (STS) measurements and computational simulations of the graphene membrane mechanics and morphology. The graphene membrane

Characteristics of Graphene for Quantized Hall Effect Measurements

June 1, 2012
Author(s)
Randolph E. Elmquist, Mariano A. Real, Irene G. Calizo, Brian G. Bush, Tian T. Shen, Nikolai N. Klimov, David B. Newell, Angela R. Hight Walker, Randall M. Feenstra
This paper describes concepts and measurement techniques necessary for characterization of graphene in the development of graphene-based quantized Hall effect (QHE) devices and resistance standards. We briefly contrast the properties of graphene produced

CODATA Recommended Values of the Fundamental Physical Constants: 2010

March 1, 2012
Author(s)
Peter J. Mohr, Barry N. Taylor, David B. Newell
This paper give the 2010 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. The 2010 adjustment takes into

Graphene: Plane and Simple Electrical Metrology?

December 7, 2011
Author(s)
Randolph E. Elmquist, Felipe Hernandez-Marquez, Mariano Real, Tian T. Shen, David B. Newell, Colin J. Jacob, George R. Jones
The development of large-area graphene has direct application to electrical standards including the quantized Hall resistance because of unique characteristics not found in conventional devices. These include symmetrical conduction by electrons and holes

Quantum Hall effect on centimeter scale chemical vapor deposited graphene films

December 7, 2011
Author(s)
Tian T. Shen, Wei Wu, Qingkai Yu, Curt A. Richter, Randolph E. Elmquist, David B. Newell, Yong P. Chen
We report observations of well developed half integer quantum Hall effect on mono layer graphene films of 7 mm × 7 mm in size. The graphene films are grown by chemical vapor deposition on copper, then transferred to SiO2/Si substrates, with typical carrier

The New SI: The Role of CODATA

December 1, 2011
Author(s)
David B. Newell, Peter J. Mohr, Barry N. Taylor
The mission of the International Council for Science : Committee on Data for Science and Technology (CODATA ) is to strengthen international science for the benefit of society by promoting improved scientific and technical data management and use. One of

Graphene Production for Electrical Metrology

June 1, 2011
Author(s)
Randolph E. Elmquist, David B. Newell, George R. Jones, Felipe L. Marquez-Hernandez, Mariano A. Real, Tian T. Shen
Many material and electronic contributions must be favorable to produce devices with strong quantum Hall effect (QHE) plateaus that are suitable for precise resistance metrology. Even so, metrologically interesting QHE plateaus have been observed in

Microscopic Polarization in the Bilayer Graphene

April 24, 2011
Author(s)
Joseph A. Stroscio, Suyong S. Jung, Nikolai N. Klimov, David B. Newell, Nikolai B. Zhitenev, Gregory Rutter
Bilayer graphene has drawn significant attention due to the opening of a band gap in its low energy electronic spectrum, which offers a route to electronic applications that is not practical with single layer graphene. The gap can be either tunable through

Evolution of Microscopic Localization in Graphene in a Magnetic Field: From Scattering Resonances to Quantum Dots.

January 9, 2011
Author(s)
Suyong S. Jung, Gregory M. Rutter, Nikolai Klimov, David B. Newell, Irene G. Calizo, Angela R. Hight Walker, Nikolai Zhitenev, Joseph A. Stroscio
Graphene is a unique material displaying high-mobility transport in monolayer-thin films. However, its properties are strongly dependent on interactions with substrates, local charges and environment. Scanned probe microscopies can be used to locally probe

Resource Letter FC-1: The physics of fundamental constants

April 1, 2010
Author(s)
Peter J. Mohr, David B. Newell
This Resource Letter is a guide to the literature describing both experimental and theoretical work on the determination of values of certain fundamental physical constants. In this Letter, fundamental physical constants are taken to be the experimentally

The Fundamental Physical Constants: A New Set of Recommended Values of the Basic Constants and Conversion Factors of Physics and Chemistry Incorporating Recent Data Has Just Been Issued by CODATA

October 16, 2008
Author(s)
Peter J. Mohr, Barry N. Taylor, David B. Newell
The Committee on Data for Science and Technology (CODATA) was established in 1966 as an interdisciplinary committee of the International Council of scientific Unions (now International council of Science). Three years later, CODATA created the task group
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