Second Generation Fractional Quantum Hall Effect

Authors

W. Pan, K.W. Baldwin, K.W. West, L.N. Pfeiffer, and D.C. Tsui

Scientific Achievement

We unambiguously confirm, for the first time, a new second-generation fractional quantum Hall effect (FQHE) state at Landau level filling n=4/11.

Significance and Impact

This confirmation opens the door for fundamental understanding the nature of the ground state of second generation FQHE states (e.g., electron correlation).

Research Details

–Carried out low temperature and high magnetic field electronic transport measurements in ultra-high mobility two-dimensional electron system.

–Observed quantized Hall plateau […]

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Elucidating the Role of Twin Boundaries in Deformation of Nanocrystalline Metals

Authors

J.G. Brons, J.A. Hardwick, H.A. Padilla II, K. Hattar, G.B. Thompson, B.L. Boyce

Scientific Achievement

Simulation results suggest that twins don’t just facilitate a single mechanism (e.g. ‘detwinning’), but that they facilitate several separate mechanisms simultaneously.

Significance and Impact

Coupled experiment and modeling reveal the dramatic and complex impact of high-density twin boundaries on microstructure evolution and deformation mechanisms

Research Details

–Cryogenic nanoindentation reveals that high densities of twin boundaries leads to substantial low-temperature grain growth during deformation

–Novel analysis […]

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Molecular Dynamics Simulations Predict Fate of Uranium in Sediments

Authors

Teich-McGoldrick, S.T., Greathouse, J.A., and Cygan, R.T.

Scientific Achievement

Large-scale molecular simulations identify structural properties of aqueous uranium adsorbed on mineral surfaces.

Significance and Impact

Detailed molecular perspective will improve the fidelity of nuclear waste performance assessment for complex natural systems in which accurate adsorption processes are difficult to assess.

This work will inform government and regulatory agencies for approving and instituting nuclear waste repositories, and guide treatment of waste sites.

Research Details

Solution structure at the mineral-solution interface identifies adsorption mechanisms […]

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Self-Regulated Fabrication of Size-Controlled Quantum Nanostructures

Authors

Xiaoyin Xiao, Arthur J. Fischer, George T. Wang, Ping Lu, Daniel D. Koleske, Michael E. Coltrin, Jeremy B. Wright, Sheng Liu, Igal Brener, Ganapathi S. Subramania, and Jeffrey Y. Tsao

Scientific Achievement

We demonstrate the use of quantum-size-controlled photoelectrochemistry (PEC) to fabricate sub-10-nm nanostructures, more specifically, InGaAs quantum dots (QDs).

Significance

Historical advances in semiconductor technology have depended on precision fabrication of micro- and nano-structures of ever smaller feature sizes. As nanostructures enter the sub-10-nm size regime, however, […]

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Control of Strong Light-Matter Coupling Using the Capacitance of Metamaterial Nanocavities

Authors

A. Benz, S. Campione, J.F. Klem, M.B. Sinclair, and I. Brener

Scientific Achievement

We present experimental evidence that the Rabi splitting observed in metamaterials-semiconductor strongly-coupled systems is directly proportional to the capacitance of the resonator

Significance and Impact

Now we know how to maximize light matter interaction between metallic nanocavities and dipoles/emitters. This could enable polariton lasing & luminescence and new types of detectors or sensors.

Research Details

–Fabricated metamaterial arrays on top a two-level using an intersubband transition in […]

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BES Highlight: Stress-Induced Nanoparticle Crystallization

Authors

Wu, Z. Wang, and H. Fan, “Stress-Induced Nanoparticle Crystallization” Journal of the American Chemical Society, 136, 7634-7636, May 28, 2014.

Scientific Achievement

Applying compressive stress to self-assembled nanoparticle arrays eliminated defects, improved structural properties, and enabled oriented crystallization at room temperature.

Significance and Impact

This is the first demonstration that pressure annealing of nanoparticle arrays enables room temperature defect reduction and long range ordering. Single crystal-like nanoparticle assemblies are expected to display efficient electrical and optical energy transfer.

Research Details

–Diamond […]

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CRF: First Direct Detection of QOOH Intermediate Shows Long Lifetime of Key Species

Authors

J.D. Savee, E. Papajak, B. Rotavera, H. Huang, A.J. Eskola, O. Welz, L. Sheps, C.A. Taatjes, J. Zádor, D.L. Osborn, Science, 347, 643-646 (2015).

Scientific Achievement

Hydroperoxyalkyl radicals—denoted QOOH—are key intermediates in autoignition chemistry, controlling the early stages of combustion. Scientists at the Combustion Research Facility directly detected this elusive intermediate for the first time.

Significance and Impact

This detailed information will improve the fidelity of models used by engine manufacturers to create cleaner and more efficient cars and […]

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Sandia and NREL Announce Two New H2FIRST Reports

Sandia National Laboratories and the National Renewable Energy Laboratory (NREL) announce the publication of two new Hydrogen Fueling Infrastructure Research and Station Technology (H2FIRST) reports on hydrogen contaminant detection capabilities and reference station design analysis.

H2USA is a public private partnership launched by the US Department of Energy in 2013 to overcome the critical barriers to hydrogen infrastructure and enable the commercialization of fuel-cell electric vehicles (FCEVs). Sandia and NREL lead H2FIRST, which supports H2USA by […]

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Statistical Mechanics with Density Functional Theory Accuracy

Density Functional Theory (DFT) calculations allow the accurate determination of ground state and transition state energies but require thousands of processing hours for each structure. Monte-Carlo (MC) calculations allow the determination of initetemperature thermodynamic and kinetic properties of disordered systems but require energy evaluations for millions or billions of structures. In a Center for Integrated Nanotechnologies (CINT) project, we have collaborated with users at several universities to combine these seemingly incompatible methods to obtain statistical […]

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High Fidelity Evaluation of Tidal Turbine Performance for Industry Partner

High performance computing at Sandia National Laboratories is playing a key role in the U.S. Department of Energy’s

Wind and Water Power Technology Office mission of advancing the commercialization of tidal energy converters; by improving their power performance and reducing their levelized cost of energy below the local “hurdle” price at which they can compete with other regional generation sources without subsidies. This was recently highlighted in a collaborative project between Sandia National Laboratories’ water power […]

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Cryogenic and Fire Damage Analysis on Liquefied Natural Gas Ships

Liquefied Natural Gas (LNG) is transported around the globe in ships the size of modern aircraft carriers, carrying as much as 75 million gallons of LNG or the equivalent of over 6 billion cubic feet of natural gas. LNG is transported in multiple cargo tanks at cryogenic temperatures of about -250 °F. Because of their double hull design, these LNG ships have an exemplary

safety record, but a large cargo tank breach could spill significant volumes […]

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Unique High Strength, Olecularly Thin Nanoparticle Membranes

Thin membrane films composed of a single layer of inorganic nanocrystal cores encoded with organic ligands are currently of great interest for a range of applications from nanosieves to electric, magnetic, or photonic devices and sensors. While these membranes have been found experimentally to be flexible yet surprisingly strong under indentation, the underlying microscopic origin of their large tensile strength remains unresolved. Sandia researchers used largescale molecular dynamics simulations to probe the fundamental mechanisms underlying […]

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Geomechanical Modeling to Investigate the Cause of Oil Leaks in Wellbores at Big Hill Strategic Petroleum Reserve

The U.S. Strategic Petroleum Reserve stores crude oil in 62 caverns located at four sites in Texas and Louisiana and currently contains over 700 million barrels. Most of the caverns were solution mined by the Department of Energy. Oil leaks have been found in two wellbores taken from caverns located at the Big Hill Strategic Petroleum Reserve in Texas. According to the multi-arm caliper survey performed by DM Petroleum Operations in 2009 and 2010, two […]

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Atomistic Molecular Dynamics of Ion-Containing Polymers

In the quest to make better batteries, researchers at Sandia performed extensive, atomistic molecular dynamics (MD) simulations of a set of ionomer melts. Ionomers are polymers that typically have a neutral backbone with a small number of charged moieties that are covalently bound to the polymer backbone. Ionomer melts, liquids containing just ionomer olecules and their oppositely charged ions, show promise as safe, solvent-free, lightweight, single-ion-conducting battery electrolytes if

their conductivity can be made high enough. […]

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Computational Fluid Dynamics & Large-Scale Uncertainty Quantification for Wind Energy

A team of Sandia experts in aerospace engineering, scientific computing, and mathematics collaborated with researchers at Stanford University to study wind-energy design problems, using computational fluid dynamics (CFD) simulations and uncertainty analyses. The project developed new mathematical uncertainty quantification techniques and applied them, in combination with high-fidelity CFD modeling, to probabilistic wind-turbine design problems. Quantifying uncertainty for this project required analyzing hundreds of simulation scenarios/ three-dimensional high-fidelity computational runs to evaluate fluid dynamic flow past […]

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Atmosphere Component in Community Earth System Model

Increasing the speed, scalability, and resolution of global climate models is a key step toward improving the ability to simulate regional details of climate change and improving our assessments of the impacts of climate change on extreme events. The

Community Earth System Model (CESM) is a community, global climate model that provides computer simulations of the Earth’s past, present, and future climate states. This comprehensive model, developed in collaboration with National Science Foundation and Department of […]

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New Report Describes Joint Opportunities for Natural Gas and Hydrogen Fuel-Cell Vehicle Markets

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Sandians Participate in 46th Annual American Geophysical Union (AGU) Conference

Fifty-six Sandians from ten Centers joined more than 22,000 geoscience professionals, students, and academics at the December AGU Fall Meeting.

Sandia staff chaired multiple technical sessions and gave dozens of presentations on topics ranging from improved climate models to performance models for underground waste storage to 3D printing and digital rock physics.

Marianne Walck (Director of Sandia’s Geoscience, Climate, & Consequence Effects Center and the Climate & Environment Program Area) co-hosted a town hall with LBNL on […]

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Resolving a Key to How Stars Transmit Energy

Working at temperatures matching the interior of the sun, researchers at Sandia National Laboratories’ Z machine have been able to determine experimentally, for the first time in history, iron’s role in inhibiting energy transmission from the center of the sun to near the edge of its radiative band.

Because that role is much greater than formerly surmised, the new, experimentally derived amount of iron’s opacity helps close a theoretical gap in the Standard Solar Model, widely […]

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Sandians Win ‘Best Paper’ Award at Photovoltaic Conference in Japan

A research team that included Sandians Clifford Hansen and Joshua Stein (in Sandia’s Photovoltaic & Distributed Systems Integration Dept.) and Katherine Klise (in Sandia’s Geotechnology and Engineering Dept.) received a Best Paper Award for their work “Photovoltaic System Model Calibration Using Monitored System Data,” presented at the 6th World Conference on Photovoltaic Energy Conversion (WCPEC) held in Kyoto, Japan, in November 2014. This paper was presented at the WCPEC’s joint “Characterization and Modules Reliability” and […]

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