Argonne National Laboratory Center for Nanoscale Materials U.S. Department of Energy

I would like to take this opportunity to introduce myself as the new Division Director for the CNM. I am very excited about taking on this new role and look forward to interacting with many of you. I joined the Materials Science Division at Argonne in 2005 and prior to that was on the faculty at the University of Oxford in the UK. My research interests are in ferroic nanomaterials; I have had particular interests in materials with potential applications in information storage systems and also the development of in situ transmission electron microscopy facilities for studying the behavior of nanomaterials.

The CNM is a vibrant division of Argonne with outstanding staff scientists and facilities and our user base is very strong. As we prepare for our upcoming review (more on this later), I have had the opportunity to look through user and staff research highlights as well as the very impressive list of publications produced by the users and staff. As a CNM user myself, I know the importance of providing a valuable user experience, and I hope that those of you who come to use the CNM's facilities and interact with the staff find this a positive experience — we very much value the outstanding science that you achieve.

The DOE triennial peer review of the CNM is taking place this year. We are in the midst of preparing the review documents, and the onsite review will take place in May. I would like to take this opportunity to thank all of the CNM users who have helped us to prepare for this important event by providing the information that was requested of you. I regard the review as an excellent opportunity for the CNM to step back from its day-to-day activities and make strategic plans regarding future directions, and it also serves as an opportunity for the CNM to showcase our exciting science through oral presentations and posters that will be presented by staff and users.

As mentioned in the last newsletter, the CNM was fortunate to receive American Recovery and Reinvestment Act funds to support five new capabilities. One of these is the tripling of the capacity of our supercomputer cluster — see the Facility Highlight for more details.

We look forward to seeing you at the CNM, and I hope that you will find all of the articles in this newsletter stimulating.

Amanda Petford-Long, CNM Director

Amanda Petford-Long

back to top

Call for Proposals Deadline: March 5, 2010

The next CNM call-for-proposals deadline is March 5, 2010. The system is now open for submissions. The Center for Nanoscale Materials holds three Calls for Proposals per calendar year - in March, July and October. We look forward to the possibility of hosting your exciting and innovative nanoscience and nanotechnology projects. (More >>)

back to top

The computing capacity of the CNM's high-performance computing cluster, Carbon, will more than double by April 2010, via the addition of new nodes based on the latest generation of Intel processors. This system is designed to facilitate large-scale modeling of nanoscale materials and experimental data analysis. With the added nodes, the expanded Carbon cluster will feature:

  • More than 2400 processor cores (8 per node), with an aggregate performance of up to 25 Tflops
  • Up to 24GB shared memory per node (3 GB/core)
  • Infiniband interconnect between all nodes
  • Standard RedHat/CentOS 5 Linux environment
  • Parallel versions of many popular software packages, such as NWChem, Dacapo, GPAW, VASP, DFTB, Q-Chem, NAMD, and MEEP, as well as specialized software developed by the Theory and Modeling Group.

Please contact Dr. Michael Sternberg (Theory and Modeling Group) for more information.

back to top

Biomimetic ammonia switch

Self-insertion of graphene flake inside phospholipid bilayer membrane

from A. Titov, P. Král, and R. Pearson, "Sandwiched Graphene-Membrane Superstructures," ACS Nano, 4, 229 (2010)

Fabrication of BiFeO3 thin-film nanostructure using electron-beam and focused-ion-beam lithography tools

For memory applications, it is imperative to reduce the size of ferroelectric capacitors without losing polarization and thermal stability. BiFeO3 (BFO) has high polarization and a high ferroelectric transition temperature, but as the lateral size shrinks, symmetry and edge effects may influence electric and strain field distributions. BFO nanocapacitors with dimensions in the 50- to 500-nm range were fabricated by using radio-frequency magnetron sputter deposition. Focused-ion-beam lithography patterned the nanostructures. A collaborative team from the University of Puerto Rico, Korea Advanced Institute of Science and Technology, Northwestern University, and Argonne National Laboratory, working with CNM's Nanofabrication and Devices Group, also studied the dependence of domain configuration and behavior on nanocapacitor shape upon oxygen annealing. Piezoresponse force microscopy (PFM) images suggest that square capacitors have a mono-domain configuration, whereas round ones exhibit a seven-domain configuration in as-fabricated states. These findings have critical implications for the development of nanocapacitors for energy harvesting ferroelectric solar cells and next-generation high-density, nonvolatile ferroelectric memories.

S. Hong et al., J. Appl. Phys. 105, 061619 (2009)

back to top

BFO nanostructure

Ferroelectric domain images of square- and round-shaped BFO nanostructure after annealing at 650°C in O2 obtained by V-PFM

Hard X-ray characterization of fly ash geopolymers

Direct evidence of the formation of discrete high-calcium nanometer-sized particles within a binder structure of a hydroxide-activated geopolymer synthesized from a low-calcium fly ash has been obtained by a diverse team from the University of Melbourne, the Universidad del Valle of Colombia, and Argonne National Laboratory working collaboratively with CNM's X-Ray Microscopy Group. The existence of such structures within geopolymers has previously been subject of much speculation. Additionally, the level of readily available and toxic chromium in a fly ash geopolymer was found to be significantly lower than the total chromium content of the precursor fly ash. Use of the Hard X-Ray Nanoprobe provided the first access to the nature of heterogeneity in real fly ash-derived geopolymers at the nanoscale employing scanning x-ray fluorescence. Geopolymers are currently being developed as an environmentally beneficial replacement for Portland cement for concrete production, offering comparable performance and cost while reducing greenhouse gas emissions by a factor of about 5.

J.L. Provis, V. Rose, S.A. Bernal, and J.S.J van Deventer, Langmuir, 25(19) (2009)

Calcium map of fly ash geopolymer

The calcium map of a fly ash geopolymer exhibits localized regions of high calcium concentration (circled). The distribution of calcium is highly inhomogeneous on a length scale of tens to hundreds of nanometers, suggesting localization as a discrete calcium-rich phase within the geopolymer gel.

Size-dependent multiple twinning in nanocrystal superlattices

Users from the University of Chicago and Argonne's Advanced Photon Source, working collaboratively with CNM's Nanobio Interfaces Group, have experimentally observed a dramatic increase of the twinning probability in self-assembled nanocrystal superstructures with increasing nanocrystal size. This is likely a result of both the size dependence of the twinning energy, and the "softer" interparticle potentials active during assembly of larger nanocrystals. The incorporation of twin planes in the fcc lattice can lower the total energy of the entire crystal by reducing the area of high energy surface facets while keeping the surface-to-volume ratio as small as possible. A deep understanding of the fundamental principles that govern self-assembly of nanoparticles into single- and multicomponent superlattices is crucially important for the development of nanocrystal-based devices, such as LEDs, solar cells, photodetectors, and thermoelectric heat-to-electricity converters. The presence of twin planes in nanocrystal superlattices also has implications in the fabrication of nanocrystal-based devices, such as photodetectors and solar cells.

S.M. Rupich, E.V. Shevchenko, M.I.Bodnarchuk, B.Lee, and D.V.Talapin, J. Am. Chem. Soc., 132, 289 (2010).

Nanocrystal Superlattices

SEM images showing morphologies of self-assembled PbS nanocrystal superlattices. (a) 3.1 nm PbS in single-domain superstructures (b) 5 nm PbS as a twin plane (c-f) 7 - 8 nm PbS multiply twinned with (c,d) decahedral and (e,f) icosahedral morphology

Imaging Raman microscopy of thin-film cuprate superconductors

High-critical-temperature superconducting wire formed from REBa2Cu3O7 (REBCO) in thin-film form on long lengths of textured metal tape is becoming a viable “zero resistance” substitute for copper in electric power applications. There is a need to reduce the size and volume fraction of nonsuperconducting secondary phases (NSPs) in the REBCO film matrix because they diminish the flow of critical current. Raman microscopy measurements of the type made possible with the state-of-the-art Raman instrumentation in the CNM Nanophotonics Group have allowed users from Argonne’s Chemical Sciences & Engineering and Materials Science Divisions to identify and spatially map the NSPs in REBCO-coated conductor tapes. They performed through-time and through-thickness Raman examinations of the evolution of NSPs during film formation. This methodology provides a means to optimize the precursor conversion parameters (e.g., temperature, O2 pressure, H2O pressure). The findings contributed to significant performance improvements in a promising DOE superconducting technology program that emphasizes energy efficiency.

V A Maroni, A J Kropf, T Aytug, and M Paranthaman, Supercond. Sci. Technol., 23, 014020 (2010).

back to top

Average Raman spectra at an intermediate stage of REBCO precursor conversion: (a) upper, (b) middle, and (c) lower sectors of the reacting film. YBCO is fully formed from the substrate level through the middle sector. Some residual unreacted precursor persists in the upper sector.

 

We are pleased to announce several new hires that are associated with the CNM's research programs in various ways. Taken together these represent a very exciting start to the year 2010.

New Staff Member

Subramanian Sankaranarayanan joined CNM on Feb. 1, 2010, as an Assistant Scientist in the Theory & Modeling Group. Subramanian received his Ph.D. in 2007 from the University of South Florida and was a postdoctoral fellow at Harvard University during 2007-2010.  His research will focus on atomistic simulations of nanoscale oxides and other nanoscale materials.

New Postdoctoral Appointments

Dario Antonio (Instituto Balseiro, Argentina) joined the Nanofabrication & Devices Group on January 25, 2010, and is working on nonlinear dynamics in nanomechanical systems (LDRD project).

Kyu Suk Baek (University of Michigan) joined the Nanofabrication & Devices Group on January 11, 2010, and is working on novel MEMS devices for minimally invasive medical procedures (LDRD project).

Arnaud Demortiere (CNRS Paris) joined the Nanobio Interfaces Group on January 4, 2010, and is working on materials synthesis for luminescent solar concentrators (LDRD project).

Albert E. De Prince III (University of Chicago), recipient of an Argonne Computational Postdoctoral Fellowship, began his tenure on January 11, 2010, in the Theory & Modeling Group. Eugene will be working on large-scale electronic structure and electrodynamics studies of nanoscale materials.

Il Woong Jung (Stanford University) joined the Nanofabrication & Devices Group on October 8, 2009, and is working on dynamically tunable plasmonic nanostructures (LDRD project).

Bon Il Koo (University of Texas at Austin) joined the Nanobio Interfaces Group on January 18, 2010, to work on an LDRD project related to nanoscale architectures for energy storage.

Bin Liu (Colorado School of Mines) began January 25, 2010, in the Theory & Modeling Group working within the Energy Frontier Research Center titled "Institute for Atom-efficient Chemical Transformations."

Chunxing She joined the Nanophotonics Group on February 2, 2010, and is working on the characterization of semiconductor nanostructures for the optimization of luminescent solar concentrators (LDRD project).

Joseph Smerdon (University of Liverpool) joined the EMMD Group on January 18, 2010, to join a DOE SISGR project on single molecule chemical imaging at femtosecond timescales.

back to top

U.S. Department of Energy Office of Science | UChicago Argonne LLC
Privacy & Security Notice | Contact Us | Site Map

The Center for Nanoscale Materials is an Office of Science User Facility operated for
the U.S.Department of Energy Office of Science by Argonne National Laboratory