Supporting the Scientific Base for Competencies Essential to Sandia Missions

DOE Office of Science

The DOE Office of Science (SC) is the single largest supporter of basic research in the physical sciences in the U.S., providing more than 40 percent of total funding in this area. Sandia has active research programs funded by:

Supports fundamental research focused in the natural sciences—in areas of direct relevance to DOE missions within chemical, condensed matter, materials, and geological sciences.

Advances environmental and biomedical knowledge that promotes national security through improved energy production, development, and use; international scientific leadership that underpins the nation’s technological advances; and research that improves the quality of life for all Americans.
The national basic research effort in advanced plasma science, fusion science, and fusion technology—the knowledge base needed for an economically and environmentally attractive fusion energy source.
Supports world-class, high-performance computing and networking infrastructures as well as supporting fundamental research in mathematical and computational sciences to enable researchers in DOE scientific disciplines to analyze and predict complex phenomena for scientific discovery.

ARPA-E-Full-Logo-v-3.0-1024x315

ARPA-E is an innovative and collaborative government agency that brings together America’s best and brightest scientists, engineers, and entrepreneurs.

The focus of Sandia’s ARPA-E program is to establish partnerships with universities, industry and other National Labs to create innovative energy solutions for the Nation through both maturation of industry capabilities and commercialization of our technologies.

  • Address Stationary and Transportation Energy pillars
  • Leverage differentiating facilities/capabilities and Research Foundations of Sandia Labs

Research Highlights

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 and thermally activated magneto-resistance at Landau level filling n=4/11.

–Measured energy gap at n=4/11, ~ 7 mK.

–Tilt magnetic field study shows that the 4/11 state is probably spin polarized, suggesting that it may be a new non-Abelian fractional quantum Hall state.

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 methods applied to LAMMPS MD simulations allow for the detailed quantification of both microstructural evolution and deformation modes as a function of initial structure.

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 of naturally occurring ions (K+) and uranyl ions (UO22+).
  • Surface charge due to adsorbed uranyl ions is consistent with spectroscopic measurements (second harmonic generation).

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, precision fabrication becomes increasingly difficult. A combination of nanometer-scale lithography with quantum-size controlled photoelectrochemistry (demonstrated here) might achieve the holy grail of simultaneous control over quantum-scale nanostructure distributions in size and space.

Research Details

  • Our initial set of samples were thin (3-20 nm) epitaxial In0.13Ga0.87N films grown under conditions similar to those used for state-of-the-art InGaN light-emitting diodes
  • Samples were sliced and suspended in a PEC cell for etching via In wire contacts. For the working electrolyte we used H2SO4 which allowed us to completely eliminate etching in the absence of light. For photo-excitation we used a tunable, relatively narrow-band (~ 1 nm linewidth) laser source.
  • QD samples were analyzed using electron microscopies and spectroscopy.

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 a semiconductor heterostructure.

–measured Rabi-splitting from transmission curves for different resonator geometries.

–correlated measurements with equivalent electrical circuit model (published recently by us) to describe the light−matter interaction in these systems.