Laboratory Directed Research & Development

Accepted Proposals

Fiscal Year 2014 LDRD Projects at SLAC
Functional Polymers for Lithium-Ion Batteries

LDRD Proposal Number: SLAC-LDRD-0001-14-2

Lead Scientist: Zhenan Bao

We will develop new approaches to address the critical issues with high density silicon-based lithium ion batteries.
This work will seed new activities in SIMEs related to battery research and prepare us for future funding opportunities from Battery Hub and California Legislature funding. 
Spatial and Time Resolving Pixel Detector-Tixel

LDRD Proposal Number: SLAC-LDRD-0002-14

Lead Scientist: Christoph Bostedt

 
The goal of the proposed project is to develop a time-resolving pixelated particle detector (Tixel) capable of detecting one hit per pixel per frame, and to demonstrate its functionality with a momentum resolving electron and ion spectrometer.
Understanding Electrochemically-Active Oxide Surfaces Far from Equilibrium at Elevated Temperatures

LDRD Proposal Number: SLAC-LDRD-0003-14-2

Lead Scientist: William Chueh

 
We will continue to investigate electrochemically-active oxide surfaces at elevated-temperature using in-situ synchrotron X-ray photoemission spectroscopy and surface diffraction. We aim to understand how charge-transfer dynamics couple to surface chemistry and structure under intense potential gradients for processes relevant for solar-to-fuel and fuel-to-electricity conversions.
Chemistry in Motion: New Approaches to Probe Enzymatic Reaction Mechanisms in Crystallo

LDRD Proposal Number: SLAC-LDRD-0004-14

Lead Scientist: Aina Cohen

 
We will confront several experimental problems that are impeding progress in structural enzymology through the development of a toolbox of new experimental methods broadly applicable to the study of enzymatic reaction mechanisms in crystallo at both LCLS and SSRL. A main scientific goal is to apply these tools to trap several key intermediates in the mechanisms of methane monooxygenase MMO [1], extradiol aromatic ring‐cleaving dioxygenase 2,3‐HPCD [2], and dye‐decolorizing peroxidase DypB [3] which have been predicted from solution studies but have yet eluded structural characterization. We will use the combination of X‐ray crystallography with optical (UV‐visible‐NIR absorption) and vibrational (Raman) spectroscopy to study catalytic mechanisms of these enzymes in crystallo.
Center for Laboratory Astrophysics

LDRD Proposal Number: SLAC-LDRD-0005-14

Lead Scientist: Siegfried Glenzer

 
To develop a new world class program in laboratory astrophysics, with the goal to demonstrate physical mechanisms that will lead to particle acceleration and the generation of cosmic rays, utilizing and developing first-principles probing techniques with particular emphasize on testing theory and numerical simulations with a unique set of laser and x-ray laser sources spanning energetic nanosecond lasers, to high power short pulse lasers to high brightness x-rays, enabled by the Matter of Extreme Conditions (MEC) instrument at the Linac Coherent Light Source (LCLS) at SLAC.
New Initiative for Synchrotron Radiation-Based Catalysis and Energy Research

LDRD Proposal Number: SLAC-LDRD-0006-14-3

Lead Scientist: Britt Hedman

 
With progress in theory, synthesis, and characterization over the past decade, “Material by Design”is finally within reach and will lead to major breakthroughs. In this LDRD proposal, we address the characterization component of the theory-synthesis-characterization-test loop for science-based design of catalysts, one of the major thrusts in SLAC’s energy strategy. Specifically, we propose to continue to (1) complete the development of x-ray techniques to characterize the interactions between molecules and surfaces of catalysts under the operation conditions of catalytic reactions, and (2) optimize the x-ray techniques, from sample handling, measurement, and online data visualization, to data analysis, to meet the needs of rapid screening of large numbers of samples. We will apply this methodology to study Fischer-Tropsch synthesis process (production of hydrocarbon fuels from CO and H2), exploiting the use of cross-over transition in high energy resolution x-ray emission spectroscopy to characterize the molecule-surface interations. Experiments will be performed under in-situ conditions.
Interfacial Photoelectrochemistry Using Oxide Heterostructures

LDRD Proposal Number: SLAC-LDRD-0007-14

Lead Scientist: Yasuyuki Hikita

 
We propose that epitaxial oxide heterostructures, grown with atomic precision using pulsed laser deposition (PLD), can provide the experimental platform to develop structures that can greatly enhance the yield. The use of highly idealized yet realistic structures will enable to identify and independently evaluate the essential features reported for polycrystalline samples. Furthermore, basic strategies to develop new design principles for the electrodes are proposed based on manipulating the electrostatic boundary conditions at oxide heterointerfaces. The technical approach proposed here can be applied more generally to study complex-oxide/electrolyte electrochemistry on firm grounds.
Towards In-Situ Growth and Spectroscopy of Complex Oxide Thin Films and Heterostructures

LDRD Proposal Number: SLAC-LDRD-0008-14-3

Lead Scientist: Harold Hwang

 

The ability to grow and engineer complex oxide thin films and heterostructures on an atomic scale has made tremendous advances over the past decade. These capabilities for materials design have the potential to broadly impact fundamental science by the creation of emergent phenomena, and the control of the electronic structure of correlated materials. Furthermore, the use of oxides for energy applications can be greatly enhanced by designing the band alignments, interfaces, and surfaces relevant for fuel cells, catalysis, and photovoltaics.

While many photon probes exist at SLAC for the study of these problems, there are currently no oxide thin film growth capabilities that can be linked in situ, which is vital given the surface sensitivity of many of the relevant measurement techniques. This project will develop a mobile ultra-high vacuum PLD chamber, designed to be compatible with existing and near future beam-lines at SSRL.

Resonant Inelastic Soft X-Ray Scattering for Material Science Research

LDRD Proposal Number: SLAC-LDRD-0009-14

Lead Scientist: Wei-Sheng Lee

 
Understand the mesoscopic emergence phenomena exhibited in the strongly correlated material is one of the grand challenges for modern material science research, which has been identified as an important basic research direction for the nation and highlighted in several BES workshop reports, including the “From Quanta to the Continuum: Opportunities for Mesoscale Science”, “Directing Matter and Energy: Five Challenges for Science and the Imagination”, “Next-Generation Photon Sources for Grand Challenges in Science and Energy”, and “Basic Research Needs for Superconductivity”. Significant insight can be gained via spectroscopic measurements on spin and charge excitations in the energy-momentum space. Recently, momentum-resolved resonant inelastic x-ray scattering (RIXS) has emerged to be a powerful tool for material science research. State-of-the-art RIXS can now resolve spin and charge excitations in energy-momentum space with an energy resolution of ~100 meV, providing crucial information in addition to those obtained by inelastic neutron scattering and angle-resolved photoemission spectroscopy. Next generation RIXS instrument with sub-hundred millielectronvolt (meV) resolution and/or femtosecond time resolution are expected to be game-changing for the material science research, which has spurred a race of building such instrument among synchrotron facilities worldwide. As material science research using forefront x-ray technique is an important strategic direction of SIMES, it is urgent to establish scientific profile in the area of RIXS measurement in a timely fashion. However, the man power dedicated to this research area is lacking in SIMES. The goal of this proposal is to build up our scientific profile in this area by forming a small dedicated research group. Financial support of one postdoctoral researcher is requested. We will conduct the proposed work using start-of-the-art momentum-resolved RIXS instruments worldwide.
Low Dimensional Quantum Materials for Energy Applications

LDRD Proposal Number: SLAC-LDRD-0010-14

Lead Scientist: Robert Moore

 
High risk Li-air Batteries (LABs) are intriguing due to their extremely high theoretical energy density, an order of magnitude larger than the theoretical energy density of conventional Li-ion batteries. Recently discovered superconducting monolayer of FeSe grown on Sr3TiO2 shows signs of transition temperatures well above the boiling point of liquid nitrogen. Single monolayers of transition metal chalcogenides demonstrate exciting and remarkable properties as a direct, tunable, semiconducting bandgap. While these systems seem vastly different, they all exist in reduced dimensions and are accessible utilizing the same research platform. With the recent DOE investment in an MBE system to couple to the new SSRL ARPES beamline, SLAC is uniquely poised to understand the fundamental material processes in reduced dimensions and find creative materials solutions to grand challenge questions. VUV and x-ray spectroscopies are the ideal tools to reveal the underlying electronic structure at the surfaces and interfaces of materials allowing for the realization of new materials with tailored properties for energy applications.
Experimental Screening Of Electrocatalysts For CO2 Reduction

LDRD Proposal Number: SLAC-LDRD-0011-14-2

Lead Scientist: Jens Nørskov

 

Photo-electrochemical reduction of CO2 to fuels (artificial photosynthesis) is one of the grand challenges to science and engineering. It has all the important ingredients: a very hard problem with the possibility of leading to gamechanging technology, if successful. The main problem is the complete lack of suitable catalysts – few materials work at all and all are extremely inefficient (high overpotentials). At SUNCAT we have worked for the last two years to analyze theoretically the best known catalyst, Cu, to understand how it works. On this basis we have developed a model of the process, which allows us to understand trends in catalytic activity from one metal to the next. The model points to the fundamental reason why no single-component metallic catalysts have been found. The model also suggests possible strategies for changing the surface properties to achieve lower overpotentials. One possibility is to have two components in the active site at the surface, and recently we have started computationally to screen for new alloy catalysts. It is essential to couple this to synthesis, characterization, and test of new ideas. This should provide feedback to the theory and ultimately provide experimental proof of the existence of new catalysts.

Some testing is taking place in the groups of Jaramillo (Stanford) and Chorkendorff (DTU), and the Nilsson group at SLAC is developing characterization techniques at SSRL for these systems. However, most of this work is fundamental in nature and will provide deep insights into a few systems. What is needed is a dedicated catalysts screening effort, which can be used to identify the promising candidates for further study. A summary of the current funding related to CO2 reduction is outlined below. The conclusion is that we do not at the moment have the necessary capacity to test our ideas experimentally on a large scale, which is why we propose to develop an electrochemical catalysts screening activity at SLAC.

Correlated Electron Physics at Oxide Interfaces

LDRD Proposal Number: SLAC-LDRD-0012-14-3

Lead Scientist: Srinivas Raghu

A pioneering set of experiments[1] involving the interface between LaAlO3 and SrTiO3 (both of which are insulators), have revealed that high mobility metallic behavior[1], even superconductivity[2], occurs as the voltage across the interface is increased. These observations are certainly of fundamental importance as they point towards a new arena of designing novel phases of matter at interfaces between distinct, highly correlated electron materials. They also have tremendous scope for energy and materials applications in the next generation of devices such as field effect transistors that are based on correlated oxides instead of semiconductors. Transport measurements in these systems suggest that superconductivity occurs when there are sizeable spin-orbit interactions[3]. Even ferromagnetism has been observed at the interface and is thought to coexist with superconductivity[4]. Since ferromagnetism is typically a phenomenon associated with strong electron-electron interactions, it is clear that the oxide interface experiments pose a rich set of problems involving the interplay between electron correlations, spin-orbit coupling and the reduced dimensionality associated with the interface.

This project aims to establish a new direction within SLAC, wherein fundamental theoretical calculations involving a variety of analytical and computational methods will be performed to understand the basic phase diagram of these systems and to predict phenomena at interfaces between other transition metal oxides.

Non-Fermi Liquid Metals

LDRD Proposal Number: SLAC-LDRD-0013-14

Lead Scientist: Srinivas Raghu

 

Is superconductivity enhanced in a metal near a quantum critical point? Can higher Tc superconductivity be realized in a metal with ill-defined quasiparticles? These questions are inspired by some of the materials of greatest interest in condensed matter physics, which continue to defy theoretical understanding. These include, for instance, the high temperature superconductors and heavy fermion systems. While the ground states of these materials are conventional, the higher temperature phases are strongly coupled phases of matter. For instance, high temperature superconductivity in cuprate and iron pnictide materials develops out of a metallic phase that bears little resemblance to a free electron model with small attractive interactions. This is visible from basic properties of this phase, such as its resistance to the flow of electrical currents. Controlled theoretical models, which reproduce all the behaviors of this phase are still lacking.

We propose a new interdisciplinary effort combining expertise in Photon Science and SIMES with that present in the PPA theory group. By combining our expertise in the methods of quantum field theory, with a deep understanding of the experimental observations of non-Fermi liquid materials, we hope to stimulate significant advances in condensed matter physics. This is an exciting and new direction for the laboratory, since it combines two distinct directorates, and takes a question-driven approach.

Towards the SLAC Femtosecond Macromolecular Micro & Nanocrystallography Facilities

LDRD Proposal Number: SLAC-LDRD-0014-14-3

Lead Scientist: Michael Soltis

 

Experiments at LCLS demonstrate exciting new possibilities in macromolecular crystallography, especially for crystals that are too small for conventional data collection at synchrotrons (e.g. nanocrystals) and for systems that suffer severe x-ray radiation damage (e.g. metalloproteins) (1-3). Although the LCLS fs pulse vaporizes crystalline samples, this happens after the extremely short x-ray pulse has given rise to a diffraction pattern that is recorded while inertia keeps the atoms in place long enough not to “blur” the pattern. Thus, the radiation damage limit is significantly extended beyond what is possible with a conventional synchrotron, and a given sample may be exposed to more photons than possible at synchrotron stations.

Diffraction to 1.8 Å was recently obtained from lysozyme crystals of only a few microns in size on the LCLS CXI station using hard x-rays (2) and it was shown that the metal oxidation state remained unchanged during the recording of a diffraction pattern from a metalloprotein (3). In a collaboration between SSRL and LCLS scientists, high resolution diffraction data (<1.4 Å) were collected from single crystals of myoglobin that were ~100 μm thick, using a goniometer-based system. These experiments demonstrate the possibility of solving structures to high resolution from micro to nanocrystals and to near atomic resolution with larger samples (~100 μm) with essentially no radiation damage in contrast to what would be expected in “conventional” synchrotron crystallography experiments.

We propose to further develop the capability for solving macromolecular structures to high resolution (1-3 Å) for several key projects that have been hindered because the crystal samples have been too radiation sensitive or too small in size; specifically, 1) the structure of the metalloenzyme hydrogenase, which efficiently catalyzes bio-hydrogen production, 2) the sub-structures of an assembly line enzyme that synthesizes complex organic molecules, including potential fuel stocks. This LDRD proposal leverages an opportunity unique to SLAC due to the colocation of SSRL & LCLS. This integrated and coordinated approach will strengthen SLAC’s leadership position in photon science based structural biology.

Modeling Conformational Ensembles of Proteins and Complexes

LDRD Proposal Number: SLAC-LDRD-0015-14-3

Lead Scientist: Henry van den Bedem

 

Macromolecules often exhibit significant conformational flexibility, especially when they interact with ligands or protein partners to form assemblies. Probing these conformational changes is essential to understanding their cellular function, yet these scientifically important molecules are often difficult to crystallize and diffract poorly. Such assemblies are studied by a variety of experimental techniques, including protein crystallography (PX) and Small Angle X-ray Scattering (SAXS). Nano-crystallography (nX) and single particle imaging data from LCLS are also being targeted at these systems. A ‘divide and conquer’ approach is typically used for structure determination, where individual components (domains or proteins) are determined at high resolution and then the entire complex is studied at lower resolution. Time-resolved SAXS can be further used to probe the dynamics. However, automatically fitting large molecules or assemblies to experimental data, allowing for their flexibility remains a challenge.

We propose to complete this computational research program to model challenging systems with experimental data from multiple sources. Our approach is to extend the innovative, robotics-inspired Kino-Geometric Sampler conformational search algorithm (KGS, [4]) to fit previously determined domains or proteins to experimental data. KGS exhibits a singularly large radius of convergence and optimally reduces the number of free parameters. These unique features enable flexible 'docking' of atomic models in the data while moderating the risk of overfitting at low resolution. We aim to automatically compute 3-D models, and to provide structural insights for systems that diffract poorly or cannot be crystallized. Our method will also provide insight into functionally relevant dynamics, especially for time-resolved experiments or a series of static structures.

Methodology Developments for Structural Studies of Post-Translational Modifications of Proteins

LDRD Proposal Number: SLAC-LDRD-0016-14-2

Lead Scientist: Soichi Wakatsuki

 

Post-translational modification of proteins, such as ubiquitination, glycosylation, phosphorylation and acetylation, play critical roles in many cellular events and function such as cell cycle control, quality control, and stem cell development. In this LDRD project, we aim to continue to develop new methodologies to discover novel functions of polyubiquitin chains and other post-translational modifications of proteins. We will further establish a research environment for protein production, purification, crystallization and biochemical and biophysical characterization. Using this infrastructure, we will enzymatically produce polyubiquitin chains of different linkages and lengths. The produced polyubiquitin chains will be used to screen protein complexes in various organisms to find new polyubiquitin signaling pathways. Novel protein complexes will be subjected to functional and structural studies using synchrotron protein crystallography and solution scattering and radiation-damage free XFEL nano-crystallography.

An Automated Pipeline For Cosmological Mock Sky Survey Production

LDRD Proposal Number: SLAC-LDRD-0017-14-3

Lead Scientist: Risa Wechsler

 
Upcoming galaxy surveys will probe fundamental physics on the cosmic frontier, including dark energy, dark matter, inflation, and neutrino masses. However, the cosmological inferences require both precise predictions of structure formation and a detailed understanding of the relationship between galaxies and the matter distribution, for which cosmological simulations play an essential role. We have identified several critical bottlenecks to efficient and accurate production of and access to simulated sky surveys that our team is uniquely positioned to address. The proposed work will focus on (1) production of multi-scale initial conditions for targeted regimes in parameter space and integration of resimulations into cosmological boxes, to improve the fidelity of modeling galaxies in large cosmological volumes with efficient runtimes, and (2) integration of post-processing codes (halo finding, merger trees, galaxy models, statistical tools) into a post-processing pipeline for more rapid analysis and development. This is a renewal of an FY12 project designed to substantially develop a new strategic direction for the computational cosmology program at SLAC, based on the existing expertise of Wechsler, Abel, and their groups.
KIPAC Initiative for Cosmic Inflation

LDRD Proposal Number: SLAC-LDRD-0018-14

Lead Scientist: Chao-Lin Kuo

 
This initiative seeks to establish KIPAC as a premier institute for the study of cosmic inflation. The funding will primarily be used to establish a large-scale CMB (cosmic microwave background) detector program at SLAC, targeting the primordial gravitational waves (tensor modes) generated during inflation. The science potential is universally recognized and well documented in many national and local prioritization committees. Timely implementation of this program will place the lab in a strong strategic position to lead the development of the receiver camera(s) of the Stage-IV CMB polarization experiment (total cost $50M–$100M) jointly supported by DOE, NSF, and private funding. In addition, the initiative will foster dialogues between theorists, observers, and experimentalists to investigate novel probes of inflation.
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