Abstracts Diffraction from a beam of laser-aligned proteins Prof. John C H Spence LBL/ Dept of Physics, Arizona State University Apparatus is under construction at ASU physics (electrons) and at the Advanced Light Source in Berkeley (X-rays) to obtain diffraction patterns from a single-file submicron liquid droplet stream. The aim is to solve proteins which cannot be crystallized, and help understand protein folding. Each water droplet contains, on average, one protein. The droplets freeze by evaporative cooling to vitreous ice. The molecules are aligned by a 100 watt CW fiber laser. All three beams , laser, X-rays and droplets, run continuously, and diffraction data is acquired continuously until adequate signal-to-noise is achieved. The laser polarization is then rotated into a new orientation using a quarter-wave plate, allowing tomographic diffraction data collection for three-dimensional reconstruction. The phase problem is solved by iterative Gerchberg-Saxton-Fienup methods. The requirements of laser power and droplet temperature needed to achieve sub-nanometer resolution and so observe the secondary structure of proteins will be described in detail, together with damping and thermal fluctuation limits. Experimental results from the droplet source are given. The project, a collaboration between ASU Physics, LBL and LLNL co-workers is described in detail in PRL 98, 198102 (2004) and Acta Cryst A61, p. 237 (2005) In press.   Dynamic observation of nanostructure growth processes Frances M. Ross IBM TJ Watson Research Center With its video rate time resolution, high spatial resolution, and wide variety of imaging modes, in situ electron microscopy provides a unique window into understanding the growth of nanostructures. In this talk I will highlight some applications of in situ microscopy to observing the nucleation and growth of nanoscale crystals under a variety of conditions. I will firstly describe self-assembly of Ge islands on Si, which is achieved by performing chemical vapour deposition in a controlled environment TEM, showing from the observations that growth is controlled by a modified Ostwald ripening process. I will then discuss the formation of Si nanowires using catalytic Au droplets, where in situ deposition and oxidation experiments demonstrate that the wire diameters are determined by Au surface diffusion. Finally, I will describe the nucleation and growth of copper clusters during electrochemical deposition, which can be observed in situ using a liquid cell. In each of these examples I will attempt to show how quantitative measurements may be used to determine the physical processes controlling growth, thereby achieving a better control of the structures produced. Diffuse Electron Scattering from Individual Dislocation Loops: Experiment and Simulation M. A. Kirk1, Z. Zhou2, M. L. Jenkins2, R. D. Twesten3, A. P. Sutton4,5 and S. L. Dudarev6 1 Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 USA. 2 Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK. 3 Center for Microanalysis of Materials, Seitz Materials Research Laboratory, University of Illinois, 104 S. Goodwin Ave., Urbana, IL 61801 USA. 4 Department of Physics, Imperial College, Exhibition Road, London, SW7 2AZ, UK. 5 Laboratory of Computational Engineering, Helsinki University of Technology, PO Box 9203, FIN 02015 HUT, Finland. 6 Theory and Modeling Department, EURATOM/UKAEA Fusion Association, Culham Science Centre, Oxfordshire OX14 3DB, UK. The elastic diffuse scattering of electrons by individual nanometer-sized dislocation loops has been measured and compared with simulations of kinematical diffuse scattering from the displacement fields of loop models. Diffuse scattering patterns unique to the loop geometry and interstitial or vacancy nature are identified. The effects of the electron beam size and deviations from strong Bragg diffraction conditions are simulated. A method to image defects based solely on elastic diffuse scattering is illustrated. Correlating dislocation behavior with macroscopic mechanical properties Ian Robertson Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign Dislocations and their interactions with other microstructural features, such as impurity atoms, precipitates, dislocations, and grain boundaries are known to determine the mechanical properties of metallic systems. However, no clear methodology exists to transfer this information from the atomic scale and the mesoscale into a constitutive model that can predict the macroscopic mechanical response especially in the transition region between elastic and plastic behavior. The ideal model should incorporate the behavior at different length and time scales within one grand multi-scale scheme. Such a scheme is, however, impractical and lower length scale models are used to provide fundamental information to serve as the foundation for the development of the next higher length scale. In this talk, I will describe recent advances in straining stage designs, present examples illustrating how in situ TEM straining can be combined with large-scale molecular dynamics simulations to provide a fundamental understanding of the interactions between glissile dislocations and obstacles, and how this information has been used to develop macroscale constitutive models that predict the mechanical behavior. In-situ nanoindentation: a novel technique for understanding nanoscale deformation mechanisms E.A. Stach1, A.M. Minor2, D. Ge2, M. Jin3, & J.W. Morris, Jr.3 1School of Materials Engineering, Purdue University 2National Center for Electron Microscopy, Lawrence Berkeley National Laboratory 3Department of Materials Science & Engineering, University of California at Berkeley Nanoindentation is widely accepted as the preferred technique to study localized mechanical deformation phenomena in materials. However, the mechanisms of deformation can only be inferred from the load­-displacement data obtained during a typical instrumented nanoindentation test. In order to elucidate the underlying physics of these process, we have developed and exploited a new technique, that of in-situ nanoindentation in a transmission electron microscope (TEM). In this technique, a voltage-actuated piezoceramic tube is used to position a sharp diamond in plane with the edge of an electron transparent sample. The tip is driven into the material in order to induce deformation and the corresponding deformation is observed in real time and at high spatial resolution. In this paper we will review the details of our experimental technique, as well as summarize our results from selected materials systems. In particular, we have studied thin films of aluminum deposited on top of microfabricated wedges of silicon, allowing us to observe such effects as initial deformation modes, size effects on hardening, grain boundary motion and dislocation nucleation, as well as the effects of solute additions on both dislocation propagation and grain boundary movement. Additionally, experiments on harder materials have permitted the observation of unexpected deformation modes. In the case of single crystal silicon, we have found a size-dependent transition from pressure-induced phase transformation to room temperature deformation by dislocation nucleation and propagation. In situ TEM study of the electric field-induced phenomena in ferroelectric ceramics  Xiaoli Tan Department of Materials Science and Engineering Iowa State University Ames, Iowa 50011 Ferroelectric oxides are important functional materials responsive to external electrical stimuli and they have found wide applications in capacitors, transducers, actuators, and random-access-memories. In real applications, these devices are subjected to strong electric fields. In this presentation, the electric field-induced phenomena in ferroelectric ceramics will be examined by the in situ TEM technique. These include the polarization switching in nanometer-sized ferroelectric domains and the grain boundary cavitation in a commercial lead zirconate titanate (PZT) polycrystalline ceramic, the domain wall fracture in a Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystal, and the transformation of incommensurate modulations in Pb0.99Nb0.02[(Zr1-xSnx)1-yTiy]0.98O3 (PZST100x/100y/2) polycrystalline ceramics. In the PZT ceramic, a cavitation process was uncovered for the electric field-induced intergranular fracture. In the ferroelectric single crystal, a preexisting crack was observed to deflect and to follow a 90° domain wall, indicating the presence of severe incompatible piezoelectric strains at the domain wall.  Focus will be placed on the antiferroelectric PZST ceramics where incommensurate modulations in the form of Pb-cation transverse displacement wave were commonly observed. The electric field-induced antiferroelectric-to-ferroelectric phase transformation was found to be accompanied with the disappearance of incommensurate modulations. The wavelength was found to be quite stable against external electrical stimuli, in sharp contrast to the dramatic change under thermal stimuli reported previously. It is suggested that the appeared incommensurate modulation is an average effect of a mixture of two commensurate modulations. The electric field-induced antiferroelectric-to-ferroelectric transformation proceeds with aligning the Pb-cation displacements, which resembles the process of 90° reorientation and 180° reversal in normal ferroelectrics. Medium Range Order in Amorphous Metals P. M. Voyles, W. G. Stratton, J. Hamann, J. H. Perepezko Materials Science and Engineering, University of Wisconsin, Madison   All of the previous work with fluctuation electron microscopy (FEM) has focused on covalently bonded systems.  We have recently shown using FEM that amorphous metals also show substantial nanoscale order.  We have studied an alloy of 92 at.% Al and 8 at.% Sm, which can be rendered glassy only by the extremely rapid quenching of melt spinning.  This alloy and related high-Al content amorphous alloy crystallize to an extremely high density of pure Al nanocrystals in an amorphous matrix.  Our FEM results show that this crystallization reaction is catalyzed by nanoscale, Al-like order in the as-spun glass.  Possible in situ experiments building on FEM in these systems will also be discussed. Surface Oxidation Kinetics Professor Judith C. Yang Materials Science and Engineering Department, University of Pittsburgh   Fundamental understanding of oxidation is important for corrosion , catalysis, as well as oxide thin film processing. As our devices approach the nanoscale, understanding their environmental stability at this length scale will be critical to their performance. Yet, these initial oxidation stages, from nucleation to coalescence of an oxide scale, is still surprisingly a terra incognita. In situ ultra-high vacuum transmission electron microscopy (UHV-TEM), is ideal for visualizing these initial oxidation stages since the structural changes can be seen in real-time under well-controlled surface conditions. The dynamic responses of Cu and Cu-Au thin films to variations in thermodynamic variables such as temperature, oxygen pressure, strain, and crystallographic orientation, were monitored. The nucleation and growth behavior of three-dimensional oxide islands demonstrate that oxygen surface diffusion is the rate-limiting mechanism for oxide formation during initial oxidation, thereby demonstrating a greater universality of heteroepitaxial concepts. Models based on surface orientation, strain development, and diffusion will be discussed to explain the formation of some of the novel oxide nano-structures. Fluctuation Electron Microscopy of Crystalline Nuclei in Amorphous Semiconductors John R. Abelson, L. N. Nittala,  R. Twesten, S. Bogle, S. Jayaraman, B. Sperling, B.-S. Lee, and M.-H. Kwon   Fluctuation electron microscopy (FEM) is sensitive to 3- and 4-body atomic correlations in amorphous solids, i.e. to topological ordering on a length scale of nanometers.  The 4-body correlation is related to the dihedral angle distribution in covalent solids, which is peaked around 60 degrees in crystalline regions but is random in an amorphous matrix.  We use FEM to detect ordered regions that may act as nuclei during crystallization processes.  (1) The chalcogenide glass Ge2Sb2Te5 is used as the active layer in phase-change data storage technologies:  when the material is thermally crystallized at > 150°C, both the optical reflectivity and electrical conductivity increase sharply; a fast melt-quenching restores the amorphous phase and the original properties.  We report differences in the FEM signature of Ge2Sb2Te5 samples between the as-deposited, annealed-but-not-crystallized, and melt-quenched amorphous states that are apparently related to the crystallization behavior.   (2) Hydrogenated amorphous silicon films can be deposited in either the amorphous or nanocrystalline phase depending on the quantity of hydrogen that is introduced during the growth process.  However, the onset of crystallinity is strongly nucleation-limited.  We compare the FEM signature in amorphous silicon films deposited near to the boundary of nanocrystallinity with the signature in films deposited without hydrogen and then post-hydrogenated.  A bimodal behavior is found: hydrogen suppresses fine-scale order but enhances larger-scale order, analogous to the kinetic evolution of subcritical vs. supercritical nuclei.  Thus, we show that FEM has a unique ability to probe the nucleation stage in the amorphous-to-crystalline transformation of covalent solids.    Sensing magnetic anisotropy by momentum resolved EELS  Yasuo Ito1, 2 and Nestor Zaluzec1 1 Electron Microscopy Center, Materials Science Division, Argonne National Laboratory, Argonne, IL 2 Department of Physics, Northern Illinois University, De Kalb, IL   Since the advent of the spin-based electronics, tremendous efforts have been focused on fabrication and characterization of nanomagnetic structures. Since the spin transport occurs through the bulk of multi-layered nanostructures, probes directly sensitive to the magnetic anisotropy of the bulk and its interfaces are of great interest. So far, intense research activities to probe the magnetic anisotropy have been centered on polarized synchrotron X-ray spectroscopy techniques. However, the spatial resolution of these techniques is currently limited to ~50 nm. Therefore, there is an urgent need for a technique capable of probing the magnetic anisotropy on length scale less than a few nanometers. In the theory of the electron energy-loss spectroscopy (EELS), electron analogue of the X-ray absorption spectroscopy, the scattering vector is shown to be equivalent to the polarization vector of x-ray.  By utilizing this relationship, momentum-resolved EELS (MREELS) signal expected to contain the information of the magnetic origin such as magnetic linear dichroism when it is applied to the magnetic materials. The methods to sense magnetic anisotropy via momentum-resolved EELS performed in TEM and STEM will be reviewed for materials containing 3d-transition metals.     Coherent Nanoarea Electron Diffraction and the Solution of Phase Problem   Jian-Min (Jim) Zuo* Department of Materials Science and Engineering and F. Seitz Materials Research Laboratory University of Illinois, Urbana-Champaign (jianzuo@uiuc.edu)   This talk reports the new electron diffraction technique using a coherent nanometer-sized parallel electron beam and how the missing phase in the diffraction pattern can be retrieved to reconstruct the image. The talk will be organized in two parts. The first section covers the electron probe formation, its coherence and recording of electron diffractions from individual nanostructures, such nanoparticles, carbon and boron nitride nanotubes. The second part describes our approach to phase retrieval and looks into the issue of the missing central beam, convergence and uniqueness of phase solutions, which are general with significance to X-ray diffraction. Examples of phase retrieval and image reconstruction include carbon nanotubes, bundles and multi-wall boron nitride tubes.   *In collaboration with  M. Gao, J. Tao, I. Vantanyants, R. Zhang, L. Nagahara, R. Twesten and I. Petrov     Atomic resolution EELS analysis of defects and interfaces in functional oxide materials R.F. Klie1, M. Varela2, J.P. Buban3, A. Franceschetti2,4, C. Joos5, S. T. Pantelides2,4, S.J. Pennycook2, and Y. Zhu1 1 Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 2 Condensed Matter Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 3 Institute of Engineering Innovation, University of Tokyo, Tokyo, 113-8656, Japan 4 Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 5 University of Göttingen, 37073 Göttingen, Germany The remarkable change in the properties of a material when it is structured on the nanoscale is driving the revolution in materials science we are experiencing today. The significant reduction in the dimensions of devices and materials means that individual grain-boundaries, or even defects will have considerable influence on their properties and have to be understood on the fundamental atomic-scale. In recent years, novel techniques have been developed in analytical scanning transmission electron microscopy (STEM) that can be used to directly study the atomic-scale structure-property relationships in these nano-scale functional materials. In particular, by using correlated high-angle annular dark-field imaging (HAADF) and electron energy-loss spectroscopy (EELS), the structure, composition and bonding can all be characterized directly with atomic column sensitivity. In my presentation, I will show how atomic-column resolved EELS in an aberration-corrected STEM can be used to study the effects of Ca-doping on the local atomic and electronic structure of tilt grain boundaries in YBa2Cu3O7-δ (YBCO). Grain boundary doping, in particular by Ca, has been shown to increase the grain boundary critical current, and it has been previously suggested that Ca2+ substitutes for Y3+ in the grain boundary to provide additional holes. I will show that in the highly strained regions of the grain boundary plane, Ca segregates to Cu and Ba sites, where it does not provide holes directly. However, due to the resulting strain relief, the oxygen deficiency in the vicinity of the grain boundary is reduced and thus the hole concentration increased. The results demonstrate that to improve grain boundary Jc, ionic size may be more important than the electronic nature of the impurity.   Oxide Surfaces: Finding the Atoms then Finding the Electrons L. D. Marks Department of Materials Science and Engineering Northwestern University Evanston, IL 60201 Oxide surfaces play an important (often critical) role in many area ranging from heterogeneous catalysis to the thin film growth of photonic or electronic devices. Despite this, our knowledge of their atomic structure is surprisingly poor. Over the last few years we have been exploring their structure, exploiting some unique electron microscopy instrumentation [1] as well as Direct Methods [2] which can provide unique structure solutions. In some cases the results we find are somewhat surprising, not what one might have expected [3]. Going beyond this, we have recently been able to determine not just the atomic positions, but also direct information about the charge density at the surfaces [4]. These results, as well as the prospects for being able to predict the surface structure of oxides in the future will be described. 1. Collazo-Davila, C., E. Landree, D. Grozea, G. Jayaram, R. Plass, P.C. Stair, and L.D. Marks, Design and Initial performance of an ultrahigh vacuum Sample Preparation, Evaluation, Analysis and Reaction (SPEAR) system. Journal of the Microscopy Society of America, 1995. 1: p. 267-279. 2. Marks, L.D., E. Bengu, C. Collazo-Davila, D. Grozea, E. Landree, C. Leslie, and W. Sinkler, Direct methods for surfaces. Surface Review and Letters, 1998. 5(5): p. 1087-1106. 3. Erdman, N., K.R. Poeppelmeier, M. Asta, O. Warschkow, D.E. Ellis, and L.D. Marks, The structure and chemistry of the TiO2-rich surface of SrTiO3(001). Nature, 2002. 419(6902): p. 55-58. 4. Subramanian, A., L.D. Marks, O. Warschkow, and D.E. Ellis, Direct observation of charge transfer at a MgO(111) surface. Physical Review Letters, 2004. 92(2). Local Probing of Electron Transport Properties and Structure Using TEM-STM   E. Olsson, L. de Knoop*, H. Olin#, H. Pettersson* and K. Svensson*   * Department of Applied Physics, Chalmers University of Technology, SE- 412 96, Göteborg, Sweden #Department of Engineering, Physics and Mathematics, Mid Sweden University, SE- 851 70 Sundsvall, Sweden   The scanning tunneling microscope (STM) can be used to image and measure properties on the nanoscale and also subnanaoscale. However, it is necessary to choose either to image or to measure since both operations cannot be performed simultaneously It should also be noted that the images contain information about the surface while processes below the surface are not directly accessible. The combination of a STM and a transmission electron microscopy (TEM) enables simultaneous imaging and measurements as well as direct imaging of the surface and the structure beneath the surface. This talk will address experiments on carbon nanotubes including electromigration and a nanopipette function using a TEM-STM [1]. Methods to extract an individual carbon nanotube for insertion in the TEM-STM holder will also be addressed. The method includes a combined focused ion beam workstation and scanning electron microscope with an in-situ manipulator [2]. Different aspects of the extraction method will be discussed.   K. Svensson, H. Olin and E. Olsson, “Nanopipettes for Metal Transport”, Phys. Rev. Lett. 93, 145901 (2004). L. de Knoop, K. Svensson, H. Pettersson and E. Olsson, “Extraction of Individual Carbon Nanotubes for Local Probing of Transport Properties”, in manuscript. Aberration correction and prospects for in-situ TEM B. Kabius Electron Microscopy Center, Materials Science Division, Argonne National Laboratory, Argonne, IL During the last 10 years several concepts for aberration correction for electron microscopes have succeeded in improving spatial resolution. Electron optics systems for correction of spherical aberration are already a valuable tool for material science research. Correction of spherical and chromatic aberration is already commercially available for SEM. Lens systems for the correction of chromatic aberration for TEM or STEM have not yet been implemented because of the current stability requirements of about 10-8 for the multipole elements. Recently, new designs for chromatic aberration correction have been suggested by H. Rose requiring a current and voltage stability of 10-7 which is attainable with present technology. Two of these new designs, the “Ultracorrector” and the “Superaplanator”, have been evaluated for the TEAM project.  Cc correction for TEM mode is important for material science problems because it improves the information limit. Cs correction improves the interpretability of HRTEM images but not the information limit. Therefore, Cc correction appears to be suited to achieve a resolution of 0.5Å in TEM mode which is one of the goals of the TEAM project. This allows high resolution along high index zone axis and atomic resolution of amorphous or glassy materials. An alternative approach to improve the information limit is to reduce the energy width of the emitter using a monochromator. A Cs-corrector would be part of this concept for improved interpretability and for allowing higher convergence angles of the electron beam to compensate the intensity loss caused by the monochromator. These two concepts will be discussed with respect to their benefits for high-resolution, EFTEM and in situ experiments.  New Insights into Thin Film Plasticity by in situ Transmission Electron Microscopy  John Balk  University of Kentucky, Lexington, KY  As the thickness of a thin metal film decreases, its strength increases rapidly and can exceed that of its bulk form by an order of magnitude. Although this is typically attributed to the motion of threading dislocations, current models predict film strengths that are significantly lower than experimentally measured values. Moreover, in unpassivated polycrystalline Cu and Au films, this strengthening persists only down to a film thickness of ≈400 nm. Below this, film strength is constant, exhibiting a plateau that extends to 50 nm film thickness. For Cu films, this regime corresponds to the “parallel glide” of dislocations, which glide parallel to and very near the film/substrate interface, despite the absence of a resolved shear stress component from the biaxial film stress. With the help of in situ transmission electron microscopy observations, it will be shown that parallel glide is the result of a diffusional stress relaxation mechanism that completely accommodates the plastic deformation in ultrathin Cu films. Plasticity in Au films also appears to be diffusion-controlled, although observations of parallel glide are not as common as in Cu. The results presented here shed new light on the thermomechanical behavior of thin films for microelectronic applications, revealing important details of the relationship between dislocations and thin film plasticity. Combining Nanoscale Synthesis and Characterization using Environmental Transmission Electron Microscope    Renu Sharma Center for Solid State Science, Arizona State University, Tempe, AZ 85287-1704 Transmission electron microscopy (TEM) has been the technique of choice for chemical and structural characterization of nanomaterials due to their infinitesimal size.  Recent advances in the instrumentation have made it possible to obtain near atomic level information of the nanoscale synthesis processes in controlled gas pressures (up to 50 Torr) and high temperature (1000 C).  These microscopes are commonly knows as environmental transmission electron microscope (ETEM) and may be equipped with a field-emission gun (FEG).  An ETEM is often used to understand the response of nanoparticles to gaseous environment and temperature at an atomic level and provides a powerful combination of in-situ imaging, diffraction and spectroscopy to obtain gas-solid reaction mechanisms of individual particles. Whereas high-resolution images and electron diffraction provide structural information, electron energy-loss spectroscopy (EELS) is used to obtain chemical information. Time and temperature resolved images and/or spectroscopy provide the reaction rates that are used to obtain kinetic and thermodynamic data. Moreover, ETEM can also be used as a nanoscale cold-wall chemical vapor deposition (CVD) reactor, and is used to obtain nucleation and growth mechanism of nanomaterials during CVD process under diverse precursor pressure and deposition temperature. This unique combination of synthesis and characterizations has tremendous time advantage over ex-situ synthesis and characterization. Practical applications of such microscope can be divided in to two broad categories: (1) transformation mechanism of nanostructures due to gaseous environment at elevated temperature and (2) controlled synthesis of nanomaterials. The first category includes examples of oxidation-reduction of catalysts e.g. three-way catalysts commonly used in catalytic converters of automobiles. The second category includes synthesis of carbon nanotubes, electron beam induced deposition of nanoparticles. Some examples form each category will be presented to elucidate different types of information that can be extracted from the in-situ data obtained using a FEG-ETEM.   Corrector technology, wait for evolution... or time for revolution!    J. Ringnalda   FEI Company, Building AAE, Achtseweg Noord 5, Eindhoven, The Netherlands   In all TEM imaging, the spatial resolution is predominantly limited by the spherical aberration and chromatic aberration of the objective lens. The aberrations cause the information in the image to be blurred. This information can be retrieved by through-focus series reconstruction or by holography. Alternatively, a more direct way is to correct the spherical aberration by incorporating a Cs corrector in the TEM column [1], thus making the point resolution equal to the information limit.  For the situation where the aberrations are corrected on the image (Objective lens correction), a system shows enhancement of the resolution all the way down to the information limit.  For the situation where the aberrations are corrected on the probe (Condenser lens correction), the probe size can be improved however system stability starts to play a more and more important role in determining the final performance of the total system.  This makes it difficult to arrive at satisfactory probe performance when upgrading existing column technologies in an evolutionary manner.   Whereas the objective lens used to be the most important aspect in terms of resolution and tilt capabilities, this requirement no longer plays a significant role in corrected systems.  Since a corrector allows a system to obtain directly interpretable resolution down to the information limit of the total microscope system [2], the value for information limit becomes the resolution-limiting specification in imaging, and therefore a key specification of the base microscope system.  For enhanced probe and analysis performance, total stability of the complete system, both electronically and mechanically, will determine the ultimately possible performance.   The ‘TITAN’ new (S)TEM corrector platform is a revolutionary new design.  A completely new column with much improved optics now means that with a monochromator, even when selecting the high resolution energy slit, the spatial resolution of the system will be less than 1 Ångström in combination with a Cs corrector on the probe.  Some recent results obtained with this system will be presented.   References [1] M. Haider, G. Braunhausen, and E. Schwan, Optik 99 (1995) 167. [2] B. Freitag et al., Ultramicroscopy 102 (2005) 209. [3] P.C. Tiemeijer, Inst. Phys. Conf. Ser. 161 (1999) 191. Polar Oxide Surfaces and Interfaces: Ex-situ and In-situ Electron Microscopy Studies Marija Gajdardziska-Josifovska Department of Physics and Laboratory for Surface Studies, University of Wisconsin Milwaukee The question of the stability of polar interfaces is closely related to that of polar surfaces of ionic solids: the apparent presence of electric dipole moments in the unit cell perpendicular to the surface/interface leads to an electrostatic instability. These effects have been studied most extensively in compound semiconductors and more recently in the more ionic insulating oxides. The previously established view that polar oxide surfaces facet into neutral faces, while surface reconstructions stabilize the compound semiconductor polar surfaces, has been altered with discoveries of reconstruction stabilized polar oxide surfaces. We will briefly review the oxide surface faceting and reconstruction mechanisms to set the stage for our most recent work on hydrogen stabilization of unreconstructed polar surface [1], and in-situ ETEM studies on interactions of oxide surfaces with water [2]. Our newest line of research is designed to explore if and how the oxide surface polarity can affect the epitaxial growth of polar oxide [3] and nitride [4] films with applications in spintronics and photonics. We combine HRTEM experiment and theory with density functional theory to elucidate the atomic and electronic structure of these novel polar interfaces and to develop fundamental understanding of polar interface stabilization mechanisms. [1] “Structure of the hydrogen stabilized MgO(111)-(1×1) polar surface: Integrated experimental and theoretical studies”, V. K. Lazarov, R. Plass, H-C. Poon, D. K. Saldin, M. Weinert, S. A. Chambers and M. Gajdardziska-Josifovska, Phys. Rev. B 71, 115434 (2005). [2] “Interaction of Oxide Surfaces with Water: Environmental Transmission Electron Microscopy of MgO Hydroxylation”, M. Gajdardziska-Josifovska and R. Sharma, Microscopy and Microanalysis 11 (2005) 1-10. [3] “Polar Oxide Interface Stabilization by Formation of Metallic Nanocrystals” V. K. Lazarov, S. Chambers and M. Gardardziska-Josifovska, Phys. Rev. Lett. 90 (2003) 216108. [4] “Selected Growth of Cubic and Hexagonal GaN Epitaxial Films on Polar MgO(111)”, V. K. Lazarov, J. Zimmerman, S. H. Cheung, L. Li, M. Weinert and M. Gajdardziska-Josifovska, Phys. Rev. Lett. 94 (2005) 216101.   Invited Speakers || Abstracts || Call for Papers || Registration || Travel & Lodging ||  Conference Program || Program Committee  MMMS Conference Home Sponsored also by: