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Primeur weekly 2011-10-03

Special

The perfect data manager ...

The Cloud

Cloud computing - current scenario, trends & key players, according to ReportsnReports ...

ROLF Group signs with HP to move technology infrastructure into the Cloud ...

IBM expands business partner initiative with new Cloud channel offering ...

Red Lambda's MetaGrid software transforms security and operations for customers with big data IT, network and Cloud infrastructures ...

Desktop Grids

Desktop Grid middleware XtremWeb-HEP 7.6.0 released ...

EuroFlash

Bull launches its new mainframe family gcos 7 systems leveraging Extreme Computing technologies ...

Airbus completes data centre transformation with HP PODs ...

"Efficient use of GPU-accelerators to solve large problems" contest third tage starts ...

Unique supercomputer complex presentation held at the Tomsk State University ...

T-Platforms Company has become a Top50 leader in the Russian supercomputer list ...

USFlash

Scientists release most accurate simulation of the universe to date ...

Mongolia's National Agency of Meteorology and Environmental Monitoring orders a Cray XE6m supercomputer ...

How graphene's electrical properties can be tuned ...

Japan's KEK Research and IBM agree to develop powerful KEK central computer system ...

Intel Labs announces latest Science and Technology Center focused on next generation of pervasive computing ...

U.S. Department of Energy selects NetApp as the storage foundation for one of the world's most powerful supercomputers ...

Oracle achieves world record result with SPECjEnterprise2010 benchmark ...

Canon and Oracle join forces to integrate Canon's imaging technologies with Oracle ...

Oracle Utilities Meter Data Management running with Oracle Exadata Database Machine and Oracle Exalogic Elastic Cloud demonstrates extreme performance in processing data from smart meters ...

Oracle announces Hybrid Columnar Compression support for ZFS Storage Appliances and Pillar Axiom Storage Systems ...

Oracle unveils the world's fastest general purpose engineered system - the SPARC SuperCluster T4-4 ...

Oracle launches next generation SPARC T4 servers ...

Oracle's SPARC T4 servers deliver record-breaking performance results ...

SDSC and SDSU share in $4.6 million NSF grant to simulate earthquake faults ...

Stampede charges computational science forward in tackling complex societal challenges ...

How graphene's electrical properties can be tuned

26 Sep 2011 Riverside - An accidental discovery in a physicist's laboratory at the University of California, Riverside provides a unique route for tuning the electrical properties of graphene, nature's thinnest elastic material. This route holds great promise for replacing silicon with graphene in the microchip industry. The researchers found that stacking up three layers of graphene, like pancakes, significantly modifies the material's electrical properties. When they fabricated trilayer graphene in the lab and measured its conductance, they found, to their surprise, that depending on how the layers were stacked some of the trilayer graphene devices were conducting while others were insulating.

"What we stumbled upon is a simple and convenient 'knob' for tuning graphene sheets' electrical properties", stated Jeanie Lau, an associate professor of physics and astronomy, whose lab made the serendipitous finding. Study results appeared on-line September 25 inNature Physics.

Graphene is a one-atom thick sheet of carbon atoms arranged in hexagonal rings. Bearing excellent material properties, such as high current-carrying capacity and thermal conductivity, this "wonder material" is ideally suited for creating components for semiconductor circuits and computers.

Because of the planar and chicken wire-like structure of graphene, its sheets lend themselves well to stacking in what is called 'Bernal stacking', the stacking fashion of graphene sheets.

In a Bernal-stacked bilayer, one corner of the hexagons of the second sheet is located above the centre of the hexagons of the bottom sheet. In Bernal-stacked trilayer (ABA), the top (third) sheet is exactly on top of the lowest sheet. In rhombohedral-stacked (ABC) trilayer, the top sheet is shifted by the distance of an atom, so that the top (third) sheet and the lowest sheet form a Bernal stacking as well.

"The most stable form of trilayer graphene is ABA, which behaves like a metal", Jeanie Lau explained. "Amazingly, if we simply shift the entire topmost layer by the distance of a single atom, the trilayer - now with ABC or rhombohedral stacking - becomes insulating. Why this happens is not clear as yet. It could be induced by electronic interactions. We eagerly await an explanation from theorists."

Her lab used Raman spectroscopy to examine the graphene devices' stacking orders. Next the lab plans to investigate the nature of the insulating state in ABC-stacked graphene. In this kind of stacked graphene, they also plan to study the band gap - a range in energy, critical for digital applications, in which no electrons can exist.

"The presence of the gap in ABC-stacked graphene that arises, we believe, from enhanced electronic interactions is interesting since it is not expected from theoretical calculations", Jeanie Lau stated. "Understanding this gap is particularly important for the major challenge of band gap engineering in graphene electronics."

Besides graphene, Jeanie Lau studies nanowires and carbon nanotubes. Her research has helped physicists gain fundamental understanding of how atoms and electrons behave when they are ruled by quantum mechanics. Her lab studies novel electrical properties that arise from the quantum confinement of atoms and charges to nanoscale systems. Her research team has shown that graphene can act as an atomic-scale billiard table, with electric charges acting as billiard balls.

Her other research interests include superconductivity, thermal management and electronic transport in nanostructures, and engineering new classes of nanoscale devices.

An educational component of Jeanie Lau's research effort is the active involvement of high school, undergraduate, and graduate students, especially minority and women, in her cutting-edge research, taking advantage of the ethnic diversity of UCR's student population and local communities. She is a founding faculty member of theUCR Undergraduate Research Journal. She also organized a "Women in Physics" lunch group that provides a friendly platform for female students, postdocs and faculty members to interact.

After receiving her bachelor's degree in physics from the University of Chicago in 1994, Jeanie Lau proceeded to Harvard University from where she received her master's and doctoral degrees in physics in 1997 and 2001, respectively. She joined UCR in 2004, after an appointment as a research associate in the Hewlett-Packard Laboratory.

Jeanie Lau's awards and honours include a Presidential Early Career Award for Scientists and Engineers, 2009; a National Science Foundation CAREER Award, 2008; the Richter Fellowship for Undergraduate Research, 1992; a David W. Grainger Senior Scholarship, 1993; and a Robert T. Poe Faculty Development Grant from the Chinese-American Faculty Association of Southern California, 2007. She has published more than 60 research articles in peer-reviewed journals.

Jeanie Lau, a member of UCR's Center for Nanoscale Science and Engineering, was joined in the research by W. Bao (the first author of the research paper), L. Jing, J. Velasco Jr., Y. Lee, G. Liu, D. Tran and M. Bockrath at UCR; B. Stanley at Caltech; M. Aykol and S. B. Cronin at the University of Southern California; D. Smirnov at the National High Magnetic Field Laboratory, Florida; M. Koshino at Tohoku University, Japan; and E. McCann at Lancaster University, United Kingdom.

The research was funded by grants from the National Science Foundation, Office of Naval Research, and the Focus Center for Functional Engineered Nano Architectonics.
Source: University of California - Riverside

Back to Table of contents

Primeur weekly 2011-10-03

Special

The perfect data manager ...

The Cloud

Cloud computing - current scenario, trends & key players, according to ReportsnReports ...

ROLF Group signs with HP to move technology infrastructure into the Cloud ...

IBM expands business partner initiative with new Cloud channel offering ...

Red Lambda's MetaGrid software transforms security and operations for customers with big data IT, network and Cloud infrastructures ...

Desktop Grids

Desktop Grid middleware XtremWeb-HEP 7.6.0 released ...

EuroFlash

Bull launches its new mainframe family gcos 7 systems leveraging Extreme Computing technologies ...

Airbus completes data centre transformation with HP PODs ...

"Efficient use of GPU-accelerators to solve large problems" contest third tage starts ...

Unique supercomputer complex presentation held at the Tomsk State University ...

T-Platforms Company has become a Top50 leader in the Russian supercomputer list ...

USFlash

Scientists release most accurate simulation of the universe to date ...

Mongolia's National Agency of Meteorology and Environmental Monitoring orders a Cray XE6m supercomputer ...

How graphene's electrical properties can be tuned ...

Japan's KEK Research and IBM agree to develop powerful KEK central computer system ...

Intel Labs announces latest Science and Technology Center focused on next generation of pervasive computing ...

U.S. Department of Energy selects NetApp as the storage foundation for one of the world's most powerful supercomputers ...

Oracle achieves world record result with SPECjEnterprise2010 benchmark ...

Canon and Oracle join forces to integrate Canon's imaging technologies with Oracle ...

Oracle Utilities Meter Data Management running with Oracle Exadata Database Machine and Oracle Exalogic Elastic Cloud demonstrates extreme performance in processing data from smart meters ...

Oracle announces Hybrid Columnar Compression support for ZFS Storage Appliances and Pillar Axiom Storage Systems ...

Oracle unveils the world's fastest general purpose engineered system - the SPARC SuperCluster T4-4 ...

Oracle launches next generation SPARC T4 servers ...

Oracle's SPARC T4 servers deliver record-breaking performance results ...

SDSC and SDSU share in $4.6 million NSF grant to simulate earthquake faults ...

Stampede charges computational science forward in tackling complex societal challenges ...