Basic Energy Sciences Advisory Committee Meeting

Omni Shoreham Hotel Washington, DCJune 6, 2005

Harriet Kung Division of Materials Sciences and EngineeringOffice of Basic Energy Sciences, Office of ScienceU.S. Department of Energy

Division of Materials Sciences and EngineeringDivision of Materials Sciences and Engineering

Reflection on BESAC Report on Theory and ComputationReflection on BESAC Report on Theory and Computation

Basic Energy SciencesBasic Energy SciencesServing the Present, Shaping the FutureServing the Present, Shaping the Future

Dramatic Progress in Theory and ModelingDFT, ab initio MD, Quantum MC, DMFT, etc.

New Computational CapabilitiesWorkstation and Cluster- Universities and Labs Massively Parallel Computers- LBNL/NERSC, PNNL/EMSL, ANL, ORNL

Theory and Computation Theory and Computation A Confluence of Opportunities in Materials Sciences and Engineering A Confluence of Opportunities in Materials Sciences and Engineering

0.78 Angstroms

Direct image of a silicon crystal showing atom columns in pairs only 0.78 Angstroms apart

A first-principles method describing the dynamics of magnetic moments in materials Charge Transport in Carbon Nanotubes

Source: A.P. Alivisatos

New Scientific FrontiersUltrasmall and Ultrafast Sciences, Quantum-Level Control of Matter and Information, Infusion of Bio Approaches and Techniques

Source: A.P. Alivisatos

New Experimental CapabilitiesTabletop Tools: STM, NMR, STEM, fs-LaserLarge Facilities: SNS, NSRCs, LCLS

Source: G.M. Stocks et al.

Source: S. Pennycook et al.

Theory and Computation in Materials Sciences and EngineeringTheory and Computation in Materials Sciences and Engineering

Electronic Structure Band structure, simulations, model development, many body theory, spin dynamics Correlation of electronic structure with materials properties; self-organized electronic structure (FQHE, stripes); superconductivity, magnetism, chemical reactivity, hardness, toughness Dynamics & fluctuations

New Materials

New combinations of atoms and new degrees of complexity, e.g., competing interactions among spin, charge, lattice, Vortex matter, Photonic Band Gap Materials, Granular Materials Nano and other low-dimensional structures Materials created by energetic processes Self assembly, pattern formation Modeling complex fluids, colloids, polymers, and biomolecular materials

Surfaces and Interfaces Electronic surface structure, surface reconstruction Patterns of crystal growth Solid – liquid interfaces, corrosive, adhesive, and electrochemical properties Defects in solids

Development of Computational Techniques Spin Dynamics, Inverse Band Structure, Linear Expansion in Geometric Objects, Algorithm Development, Hyperdynamics

Nanoscale ScienceNanoscale Science

Biomimetic Materials and Energy Processes Biomimetic Materials and Energy Processes

Correlated Electrons in Solids Correlated Electrons in Solids

Excited Electronic StatesExcited Electronic States

Magnetic Spin Systems & Single Electron DevicesMagnetic Spin Systems & Single Electron Devices

Defects in Solids Defects in Solids

Control of Energy, Matter & Information at the Quantum LevelControl of Energy, Matter & Information at the Quantum Level

Ultrafast Physics and ChemistryUltrafast Physics and Chemistry

Control of Chemical TransformationsControl of Chemical Transformations

New Opportunities Identified by the Report Match DMS&E PrioritiesNew Opportunities Identified by the Report Match DMS&E Priorities

Simulations of Self Assembly of Gold NanoparticlesSimulations of Self Assembly of Gold Nanoparticles

► Simulations have explored formation of nanocrystals composed of passivated gold clusters.

► Assembly begins by formation of chain structures. The length of the chains formed as well as the nanoparticle size and temperature all affect the resulting properties such as tetragonality, elastic properties of the lattice.

► Another related project has been examining how nanoparticles can be tailored to encourage chosen structures. (i.e., polymer tethers, reactive regions, etc.)

New insights on self assembly of nanoparticles were provided by atomistic simulations.DMS&E Theoretical Condensed Matter Physics CRA

Atomistic simulations are being used to gain insight on the unit processes involved in deformation. This array of pyramids was revealed by computer simulations as the structure of Cu/Ni interfaces and consists of defects known as stair-rods and stacking faults. The computer models also indicate that this structure is very resistant to deformation.

Theoretical Strength - Deformation in Nanostructured MetalsTheoretical Strength - Deformation in Nanostructured Metals

Cu

Ni

Cu

Ni

As-deposited Under applied strain 3-D view of the interface structure

Computation studies shed light on the role of defects in controlling ultimate strength in solids. DMS&E Mechanical Behavior CRA

k||-resolved contributions from Fe(001) minority states to the STM current (n1) and corrugation (n2) for different applied fields. Yellow (red) denotes positive (negative) values.

Charge density above the Fe(001) surface showing the anticorrugation for an applied electric field.

Scanning Tunneling Microscope data are normally interpreted as directly giving the positions of the atoms on a surface. Calculations of the effect indicate situations where the electric field induced by the tip modify the electronic densities and give false indications for the atomic positions.

New Ideas Underlie Experimental InterpretationsNew Ideas Underlie Experimental Interpretations

Angular Resolved Photoemission experiments reveal the breakup of the Fermi surface in high Tc cuprate superconductor by forming pseudogap, starting at about 180K and reaching the isolated points for the superconducting state at 85K. That these points exist is strong evidence for the d-wave character of the superconductivity. The ability to see this detail was enabled by the theorist’s realization that one could characterize the energy dependence of the experimental data that made it possible to extract the information.

Theoretical efforts allow interpretations of photoemission to reveal pseudogap in superconducting cuprate and account for tip effect in STM observations.

DMS&E Theoretical Condensed Matter Physics CRA

Theory of ExperimentsTheory of Experiments

To advance frontiers in computational materials science through strong coupling with table-top experimental efforts as well as at BES user facilities to benchmark theoretical models and to guide experimental designs.

Theory vs. Experiment:silicon nanoclusters

Excited State Electronic StructureExcited State Electronic Structure

Large Facilities Science Table-top ScienceTheory and Computation

CMSN Cooperative Research TeamsCMSN Cooperative Research Teams

Current Teams

Under

DMS&E

Support

Excited State Electronic Structure and Response Functions: Louis, Rehr Magnetic Materials Bridging Basic and Applied Science: Stocks, Harmon Microstructural Effects on the Mechanics of Materials: Wolf, LeSar Fundamentals of Dirty Interfaces: From Atoms to Alloy Microstructures:

Rollett, Karma Predictive Capability for Strongly Correlated Electron Materials:

Scalettar, Pickett

Potential Additions

Multiscale Studies of Formation and Stability of Surface-based Nanostructures

The mission of the Computational Materials Science Network is to advance frontiers in computational materials science by assembling diverse sets of researchers committed to working together to solve relevant materials problems that require cooperation across organizational and disciplinary boundaries.

Collaborative Programs to Tackle Complex Grand ChallengesCollaborative Programs to Tackle Complex Grand Challenges

For more information on CMSN: http://www.phys.washington.edu/users/cmsn/

Materials Theory Institute (MTI)Materials Theory Institute (MTI) A visitors program designed to attract leading scientists with expertise

complementary to that available at the host institutions

Foster growth and expansion of theoretical science by catalyzing interdisciplinary interactions and collaborations

Format enables mobile, well focused, and highly interactive character research

Tackle a rich variety of the compelling and topical scientific problems that strengthen and expand the capabilities of the home institution

Regular workshops focused on the most urgent emerging topics to attract leading world scientists to advance the field and contribute to the creative and stimulating atmosphere of the Institute

Collaborative Programs to Tackle Complex Grand ChallengesCollaborative Programs to Tackle Complex Grand Challenges

DMS&E currently supports MTI projects at ANL and BNL

DMS&E recognizes many outstanding materials sciences issues could benefit considerably from high-end computing.

Access to high-end computer resources is a limiting factor for DMS&E researchers.

Reliability of time allocation over a period of several years is critical for optimum design of computation strategies.

Availability and Access to DMS&E Computational ResourcesAvailability and Access to DMS&E Computational Resources

DMS&E is pursuing options to• Seek further resource allocations within Office of

Science/ASCR• Leverage resources at other computer centers (e.g.,

NSF Centers)• Expand DOE Centers• Provide additional clusters

Software as Shared Research InfrastructureSoftware as Shared Research Infrastructure

Hyperdynamics and other multiple time scale techniques

Geometric Cluster Algorithm (GCA) for complex fluids simulation

Linear Expansion of Geometric Objects (LEGO)

Inverse band structure methods

Solving for many electron wave functions

Shared software and codes in CMSN Collaborative Research Teams

Current efforts in algorithm and technique development:

Compelling future needs to develop new algorithms and codes for general use at DOE’s leadership-class computing facilities

GCA yields several orders of magnitude efficiency improvement of complex fluids simulations

Bridging intermediate steps to incorporate the effects of rare but critical events into dynamic simulations

Expansion of Complex Solids enables wide search for lowest energy structures using search algorithms

New Avenues to ComputationNew Avenues to Computation

Spintronics – dissipationless spin currents

Quantum Computing – magnetic molecules & entangled states

x: current direction y: spin directionz: electric field

GaAsE

z

y

xAn equivalent to an “Ohm’s law” was discovered for quantum spintronics- Spin current can be induced by the electric field thru the spin-orbit coupling, and it can flow without dissipation!

kijkspinij EJ

Science 301, 1348 (2003)

►►Theoretical effort expanding on using spin as the Theoretical effort expanding on using spin as the mechanism of quantum computing and showing mechanism of quantum computing and showing the spin-orbit coupling can help rather than being the spin-orbit coupling can help rather than being only a loss mechanism.only a loss mechanism.

►►Starting a project based on using the spin Starting a project based on using the spin resonance of N isolated and positioned by an resonance of N isolated and positioned by an enclosing Cenclosing C6060 molecule. molecule.

Increase support for investigators at universities and labs – Increase support for investigators at universities and labs – particularly in nanoscience, correlated electrons systems, particularly in nanoscience, correlated electrons systems, defects in solids, electronically excited states defects in solids, electronically excited states

Provide additional computer clusters Provide additional computer clusters

Encourage theorists and computer scientists to work with Encourage theorists and computer scientists to work with facility users and other experimental effortsfacility users and other experimental efforts

Expand collaborative effortsExpand collaborative efforts

Enhance usage of high-end computers Enhance usage of high-end computers

Support develop new algorithms and codes for general useSupport develop new algorithms and codes for general use

Support research in new forms of computing (spintronics, Support research in new forms of computing (spintronics, quantum computing)quantum computing)

Outlooks for Theory and Computation in DMS&EOutlooks for Theory and Computation in DMS&E

The DMS&E FY2006 Budget includes an increase of $3M for theory and computation in nanoscience.

DMS&E Challenges and Strategies in Theory and ComputationDMS&E Challenges and Strategies in Theory and Computation

Challenges: Challenges: Build a “properly balanced” program under resource constraints

Maintain a coherent basic unity of theory, computation and experimental activities

Investment StrategiesInvestment Strategies Seek close coupling with nanoscience

Influence BES User Facilities to enhance support for theory and computation

Expand efforts through new funding opportunities (e.g., Hydrogen Fuel Initiative)

Contribute to and take advantage of BES strategic growth areas (i.e., ultrafast science, energy security research)

Thank You!Thank You!The report reinforces DMS&E investment

strategies and will guide our future theory and computation activities.