MIT Reports to the President 1994-95

Center for Materials Science and Engineering

In September of 1994, the Center for Materials Science and Engineering (CMSE) at MIT was awarded one of the first National Science Foundation Grants under the new Materials Research Science and Engineering Center (MRSEC) program. After a year-long competition that began with more than 100 contestants, CMSE won the largest of the 11 grants creating new Centers at universities throughout the nation. We describe below the mission of CMSE and the methods used to reach its goals, which were applauded by the NSF's mail and panel reviews.

MIT has an extraordinarily strong and broad effort in materials science and engineering involving approximately 110 faculty members in 11 departments in the schools of science and engineering. Several centers and laboratories at MIT have been established to facilitate industrial participation in such research. There is great opportunity in this environment to solve problems that address the needs of society more effectively by encouraging collaboration. Thus, CMSE has a special mission: to foster collaborative interdisciplinary research and education in the fundamental science of materials and in the engineering of materials for specific applications. CMSE not only promotes collaboration among MIT faculty trained in different disciplines, but also between MIT researchers and the researchers of other universities, industry, and government and nonprofit laboratories.

Collaborative research is encouraged through several mechanisms: interdisciplinary research groups (IRGs), shared experimental facilities (SEFs), infrastructure enhancement, and outreach programs. The IRGs, described below, are composed of MIT faculty who, with their students and postdoctoral associates, wish to investigate fundamental scientific questions and pathways to reach significant technological goals that can only be properly explored in a collaborative, multidisciplinary mode. These problems are too large in scope to be addressed by individual faculty members and their students. Collaboration is essential for materials-related science and engineering, even for individual investigators, because such research requires very sophisticated equipment and infrastructure. CMSE provides a mechanism for the purchase and supervision of such equipment in its SEFs. The equipment is made available to the members of the IRGs, individual MIT investigators, and researchers from other university, industrial, government, and nonprofit laboratories. In these facilities, students, postdoctoral associates, and industrial researchers working on different topics intermingle and transfer expertise and technology across traditional disciplinary boundaries. CMSE also supervises the operation, maintenance, and improvement of the Vannevar Bush building, thus providing the infrastructure necessary for first class materials research. Researchers from four departments are intermixed in the building, facilitating interdisciplinary cooperation.

In preparation for the competition for MRSEC grants, proposals for new IRGs were stimulated by notifying members of the MIT materials community early in 1993. After an initial screening of 12 group proposals, eight were subjected to detailed review by the Internal Advisory Committee (IAC) and by other knowledgeable MIT faculty, and each of the eight were also reviewed by at least two referees from outside MIT. The internal and external referees were asked to rate the proposal with regard to five criteria: the past research performance of the senior investigators, the likelihood of important scientific results from the proposed research, the coherence of the IRG, the interdisciplinary quality of the IRG, and the potential technological impact of the research. Five of the groups were rated excellent and were included in the proposal. Each IRG was also reviewed by a new CMSE Science and Engineering External Advisory Board (SEEAB).

CMSE also provides seed funds. While preference is given to young faculty, CMSE uses these funds to support research that has the potential of redefining the direction of an existing IRG or leading to the creation of a completely new IRG. Seed funding provides CMSE with the flexibility necessary to initiate high-risk research. During the past year CMSE held an open competition for seed grants. Proposals were solicited from all junior faculty in the departments of Aeronautics and Astronautics; Chemical Engineering; Chemistry; Civil and Environmental Engineering; Electrical Engineering and Computer Science; Earth, Atmospheric, and Planetary Sciences; Materials Science and Engineering; Mechanical Engineering; Nuclear Engineering; Ocean Engineering; and Physics. Nineteen proposals were submitted, of which nine were funded. Recipients of seed funding included four women. Past seed funding has led to the founding of several start-up companies that provide more than 100 jobs, demonstrating both the importance of seed funding and the value of basic research in creating wealth.

INTERDISCIPLINARY RESEARCH GROUPS

IRG-I. Microphotonic Materials And Structures

The purpose of this program is to explore the fundamental nature, synthesis, and properties of Photonic Band Gap (PBG) materials and to exploit these properties for the creation and control of electromagnetic radiation. These materials are a composite of a periodic array of macroscopic dielectric scatterers in a homogeneous dielectric matrix. A PBG material affects the properties of traveling electromagnetic waves in much the same way that a crystal of atoms affects the properties of electron waves. Consequently, photons in PBG materials can have band structures, gaps, localized defect modes, and surface modes. By allowing the trapping, localization, and channeling of light with very low loss, these new materials have the potential of completely revolutionizing the basic elements of photonic and optoelectronic integrated circuits. The bending radius of a conventional planar waveguide is limited to 1 cm by scattering losses; this geometry is incompatible with integrated photon distribution on a chip. A PBG material will allow a 10 mm radius bend, and provide a gateway to microphotonics. The research addresses a broad range of fundamental issues in novel synthesis pathways for inhomogeneous microstructures, new photonic phenomena, and components for well-defined systems applications. The group has already fabricated and begun to characterize a one-dimensional PBG waveguide with a bandgap centered at 5 um, composed of a set of colinear air holes in Si.

Participating faculty and departmental affiliations: Professors H. A. Haus, E. P. Ippen, L. A. Kolodziejski, and L. R. Reif (Electrical Engineering and Computer Science); E. R. Brown (Lincoln Laboratory); L. C. Kimerling (Materials Science and Engineering); and J. D. Joannopoulos (Physics).

IRG-II. Molecular And Supermolecular Engineering Of Polymeric Systems With Novel Electronic And Optical Properties

The objective of this group is to develop the chemistry and molecular-level processing needed to control and manipulate the molecular and supermolecular organizations of macromolecular systems with novel electrical and optical properties. The development and utilization of combined molecular/supermolecular engineering schemes will make it possible to design and fabricate complex, multiphase or multicomponent systems with controllable molecular architectures and well-defined morphological arrangements. Thus, it will be possible to create multi-component systems in which each component serves a well-defined function and is molecularly positioned to achieve a specific and tunable electrical, optical, or chemical response. The juxtaposition of different components, such as semiconductor nanocrystallites and conjugated polymers, may result in new and useful electronic and optical behavior. Applications of interest include highly anisotropic electrically conducting films, photonic devices, periodic dielectrics, and thin film electroluminescent and energy storage devices. For example, the group has recently fabricated green and blue light emitting diodes using conducting polymers and polymer/semiconductor-nanocrystal heterostructures.

Participating faculty and departmental affiliations: Professors R. E. Cohen (Chemical Engineering); M. Bawendi, R. R. Schrock, and R. J. Silbey (Chemistry); and M. F. Rubner and E. L. Thomas (Materials Science and Engineering).

IRG-III. Phase Behavior In The Presence Of Quenched Randomness And Frustration

Cooperative behavior in the presence of frozen-in randomness, i.e. ordering in the presence of quenched disorder, permeates all of materials science. Whereas phase changes in perfect systems are well-understood, the disorder challenges our ability to understand even qualitative effects and to make precise predictions and measurements. Cooperative phenomena in the presence of quenched randomness may also underlie fundamental mechanisms of life sciences and have applications to information sciences in, for example, neural networks or coding-decoding processes. Much of what is understood about the consequences of quenched randomness is based on piecemeal results rather than exhaustive, consistent experimental and theoretical studies. This group plans to effect such a study. They will probe this one fundamental problem, ordering under quenched disorder, from different directions while requiring interconnected and mutually consistent interpretations. Model systems proposed for study include gels with random distributions of positive and negative charges and random antiferromagnets. The gels have recently received attention for their potential application in many different arenas.

Participating faculty and departmental affiliations: Professors C. W. Garland (Chemistry); and A. N Berker, R. J. Birgeneau, M. Kardar, J. D. Litster, and T. Tanaka (Physics).

IRG-IV. Structure, Chemistry, And Transport Properties Of Intercrystalline Interfaces

The properties of polycrystalline materials are largely dominated by the properties of their surfaces and grain boundaries. Oxides possess the greatest range of interfacial properties of scientific and technological interest, owing to a richness of chemical and electronic phenomena not found in most other materials. However, due to greater complexity, these materials are at the same time the least understood. The goal of this IRG is to develop a unified and comprehensive understanding of the role of atomic level structure, chemistry, and local electronic structure in determining the physical properties of crystal interfaces. Towards this goal, a collaborative effort in the growth, detailed characterization, and computational modeling of grain boundaries in model oxides is proposed. The two materials chosen for study, TiO2 and ZnO, have technological applications that depend on the behavior of their interfaces: TiO2 is the primary opacifying component in paint and ZnO is the material of which varistors are made. The successful growth of single grain boundaries in these oxides and the use of electron microscopy to study their chemistry on the nm length scale has enabled this group to approach this problem in a way never before possible.

Participating faculty and research staff and departmental affiliations: Professors R. W. Balluffi, Y.-M. Chiang, H. L. Tuller, J. B. Vander Sande, and B. J. Wuensch (Materials Science and Engineering); and Dr. A. J. Garratt-Reed (CMSE).

IRG-V. Transition Metal Oxides

The discovery of high-temperature superconductivity in copper oxides has renewed interest in the more general problem of transition metal oxides, where strong correlations between the electrons are known to play a key role. For example, the parent compound La2CuO4 is an antiferromagnetic insulator, contrary to the prediction of band theory, and becomes metallic and superconducting when doped. Many believe that the superconductivity is a new manifestation of the correlated behavior of the electrons in the two-dimensional copper oxide layers. It follows that the physics of strong correlations must be better understood before the superconductivity can be explained. The goal of this group is, therefore, to study the properties of transition metal oxides in order to guide the development of a theory of correlated systems and ultimately explain the mechanism of high-Tc superconductivity. The group's strategy for reaching its goal has three parts: detailed studies of the magnetic, electronic, and optical properties of single crystals, development of a theoretical framework for the analysis of the data, and a search for new compounds. The growth of large single crystals for neutron scattering experiments is a unique strength of this effort. These crystals made possible the discovery of low energy optical excitations in undoped copper oxides like La2CuO4.

Participating faculty and departmental affiliations: Professors R. J. Birgeneau, M. A. Kastner, and P. A. Lee (Physics); and H.-C. zur Loye (Chemistry).

MATERIALS EDUCATION, HUMAN RESOURCE DEVELOPMENT, AND OUTREACH

CMSE's programs contribute to the education of both undergraduate and graduate students in a variety of ways. A joint program with the Materials Processing Center (MPC) combines NSF/MRSEC support with industrial funds to bring students from all across the nation to MIT in the summer to become involved in materials research. The SEFs are also important in undergraduate education. Courses, such as those in X-ray scattering and microfabrication, teach the students to use processing and characterization facilities and to carry out research projects using the equipment. A course entitled Materials Synthesis and Processing, taught by the Department of Materials Science and Engineering and initiated with partial NSF support, uses the SEFs extensively. In addition, short courses are taught using the facilities during the Independent Activities Period. At the graduate level, CMSE plays a critical role in the education of almost all the students at MIT who do materials-related research. In addition to those involved in the IRGs, the shared facilities are used by graduate students from 11 academic departments.

COLLABORATION WITH INDUSTRY AND OTHER SECTORS

CMSE collaborates with other laboratories and centers at MIT that carry out materials-related research and engineering with direct involvement of industry and other sectors. Collaborations are especially active with two of these, the MPC and the Microsystems Technology Laboratories (MTL). CMSE collaborates with these centers through joint sponsorship of research, joint publications, and joint symposia. MPC and CMSE have a joint Industrial Advisory Board, which reviews the effectiveness of collaboration between CMSE and industry and recommends ways of enhancing it. The board also advises CMSE about opportunities for modifying its research programs to address society's needs. MPC has begun to develop aggressively industrial participation in the appli-cation of the results of IRG research through working groups and workshops. The cost of equipment for CMSE facilities is shared by MTL and MPC whenever appropriate, and CMSE facilities are modified in coordination with these organizations to assure that the overall spectrum of facilities offered by MIT is as broad as possible without unnecessary redundancy.

The SEFs are a critical feature of CMSE's collaborations with non-MIT personnel. The facilities are made available to any researcher from a nonprofit institution and to industrial researchers when equivalent facilities are not available commercially. During the past year, CMSE facilities have been utilized by 26 commercial organizations and 11 outside academic institutions. A research manager has been hired to assure that the SEFs meet the needs of this wide variety of users. The current CMSE/IBM X-ray participating research team (PRT) at the National Synchrotron Light Source (NSLS) at Brookhaven, the CMSE/IBM/McGill PRT under construction at the Argonne Advanced Photon Source (APS), and the Brookhaven/CMSE/AT&T/Exxon neutron scattering PRT at the Brookhaven High Flux Beam Reactor are very special facilities constructed and operated with direct industrial and government laboratory collaboration. These PRTs and the neutron diffraction PRT at the National Institute of Standards and Technology (NIST) provide time for use of facilities to users from all sectors. Finally, several of the IRGs propose direct research collaboration with industry and other sectors. This is important for exchange of knowledge and the education of graduate students, for it provides them with direct experience of industrial research.

Affirmative Action

Two permanent members were added to the staff during the past year. Neil Rowlands joined the administrative staff as research manager in September, and Carol Breen was appointed to the support staff in November. One male postdoctoral associate, Laurence Lurio, was appointed on June 15, 1995. Departures from the Center's staff over the past year include research staff members Hans Jenssen, who retired August 31, 1994; Arlete Cassanho, who resigned in August of 1994; Leonard Sudenfield, who resigned April 30, 1995; and Franklin Payne, who retired June 30, 1995. In addition, one research staff member, John Martin, passed away in August.

Of the 10 students participating in the CMSE Undergraduate Research Opportunities Program, funded by the National Science Foundation as part of the MRSEC Program, four were men and six were women, one of whom, Kamilah Alexander, is African-American. Again this summer, CMSE is collaborating with the MPC in sponsoring a joint ten-week summer internship program. Nine interns were selected from applications submitted by 166 undergraduates from both MIT and other universities from around the country. Four of these scholars are women and one is an African-American man. The interns include Aristotelis Asimakopoulos (California Institute of Technology), Behin Behrang (Yale University), Clifford Leslie (University of Washington), Douglas Harris (MIT), Carol Ouellette (Swarthmore College), Danielle Russell (MIT), Andrea Santoro (Carnegie Mellon University), Jason Sebastian (University of Illinois at Urbana), and K. Jessica Thomas (Yale University).

As part of its outreach program, CMSE participates in the cooperative employment in its shared experimental facilities of students from Northeastern University and Wentworth Institute. Of the six students employed this year, one was a woman and two were African-American men. Jason Abdullah, Brian Gregor, Elizabeth Harmon, Sleamms Petit-Maitre, Costas Pitsillides, and Andrew Williamson worked as co-op students in three of the Center's SEFs over the course of the past year.

CMSE also participates in the Cambridge Teenwork program that fosters after school and summer office employ-ment of Cambridge high school students. An Hispanic young woman, Jessenia Marquez, worked for the entire school year, and continues to work throughout the summer.

The Center continued its very successful science and engineering summer day camp for seventh- and eighth-grade students from a local public school who are members of underrepresented minority groups. The students were supervised by volunteer faculty and staff, as well as five MIT students, including one African-American man, three African-American women, and one Hispanic woman. These students were Arely Benavides, Sharonda Bridgeforth, Nikki Caruthers, Dawne David, and Lakisha Powell.

In our recent NSF MRSEC proposal, we proposed to initiate the CMSE graduate minority research assistant (RA) program to fill the need for support for minority students in their last two years of graduate study. During the 1994-95 academic year, the Center provided RA support to an African-American woman in the Department of Physics and an Hispanic male in the Department of Chemistry. In addition, seed funding was granted to one female faculty member working in the field of materials science and engineering who is a member of an under-represented minority group.

Marc A. Kastner

MIT Reports to the President 1994-95