This award supports computational and theoretical research, and education on Boron nanomaterials. Theoretical work in materials physics provides models that link microscopic mechanisms to observed phenomena such as magnetism, optical response, elastic and plastic behavior, or unusual charge transport. The PI will apply accurate first principles theoretical techniques to study the structure, stability, and electronic states of boron nanostructures. Boron nanomaterials have been the subject of increasing scientific interest and investigation in recent years. One driving force is that such boron systems should have novel and unusual structural, mechanical, and electronic properties. These properties differ from those of well-known nanomaterials such as carbon nanotubes and may prove robust and useful in device applications. So they may enlarge the library of nanoscale materials properties that are accessible and modifiable. The PI has recently discovered a novel class of boron nanostructures with higher stability than those known to date. He has provided a physical picture of the nature of bonding in these and other boron nanosystems that explains the reasons for the stability of the new structures. These initial findings lay a firm foundation and also open new, unexplored, and exciting areas of investigation. More generally, research in this area furthers our understanding of the atomic geometries, stability, unusual bonding schemes, and electronic behaviors of nanostructures and reduced dimensional systems. A goal of this research is to advance our understanding of nanostructures in multiple directions. These include the properties of two-dimensional sheet-like forms of boron?the boron analogues of graphene for carbon nanotubes, boron nanotubes constructed from these sheets, and the response and properties of boron sheets and nanotubes when doped with a variety of atoms. This research will be enhanced through collaboration with the Pfefferle group at Yale, a group that can fabricate and carry out experimental studies boron nanotubular structures. This intersection of theory and experiment holds potential for theory to have a direct impact on the field.
This award supports educational activities that aim to disseminate knowledge and interest in computational condensed matter theory through mentorship of graduate and undergraduate students. The PI plans to develop a curriculum for an advanced graduate-level solid-state theory course. Undergraduate students will continue to be trained and will perform research on boron nanostructures while learning solid-state and computational physics. The PI will continue and expand his participation in science education at minority-dominated local public schools by: (a) helping plan and judge at science fairs and competitions, (b) mentoring and tutoring students in a robotics class at a local public school, and (c) developing a set of presentations for young students to introduce them to the key materials physics and technological ideas behind common objects such as computer chips, LEDs, CD players, lasers, displays, flash memory, etc. The presentations are aimed both at educating young students and captivating the interest of those who may consider a degree or career in science or engineering.
NONTECHNICAL SUMMARY:
This award supports computational and theoretical research, and education on materials and structures of atoms that involve the element boron and have at least one dimension that is very small, at most a few billionths of a meter in length or, put another way, on the length scale of a few atoms. The PI will use computer simulations based on powerful algorithms and software to predict the properties of boron nanostructures. Of particular interest is whether there are specific arrangements of boron atoms, like sheets or tubes, that are particularly stable or able to withstand various physical and chemical stresses. Do these structures have interesting electronic and chemical properties? Similar structures based on carbon, like nanometer diameter tubes and nanometer scale ?soccer balls,? are much better known. They hold potential to form the basis of future technologies for electronic devices and sensors. Boron based nanoscale structures are less well studied, but recent advances suggest that they may possess advantages over their carbon analogs or may provide useful flexibility in the quest to develop electronics on the nanoscale. Boron has a rich chemistry and is of considerable fundamental interest.
This award supports educational activities that aim to disseminate knowledge and interest in computational condensed matter theory through mentorship of graduate and undergraduate students. The PI plans to develop a curriculum for an advanced graduate-level solid-state theory course. Undergraduate students will continue to be trained and will perform research on boron nanostructures while learning solid-state and computational physics. The PI will continue and expand his participation in science education at minority-dominated local public schools by: (a) helping plan and judge at science fairs and competitions, (b) mentoring and tutoring students in a robotics class at a local public school, and (c) developing a set of presentations for young students to introduce them to the key materials physics and technological ideas behind common objects such as computer chips, LEDs, CD players, lasers, displays, flash memory, etc. The presentations are aimed both at educating young students and captivating the interest of those who may consider a degree or career in science or engineering.
The rapidly growing field of nanoscience promises to bring forth newmaterials with interesting and useful properties that can be harnessedfor advancing knowledge and improving human life. What makesnanoscience both interesting and challenging is that the structuressynthesized or studied are so small and contain so few atoms that theydo not behave like more conventional bulk materials. In part, this isdue to the large surface area exposed as well as the new types ofbonds and bonding arrangements favored by the reduced sizes andconfined geometries. This project has focused on understanding the properties ofnanostructures containing boron either in pure form or when combinedwith metals (such as magnesium, titinium, sodium, lithium, etc.) Theconstitutent atoms in boron nanostructures show very unusual bondinggeometries that change the properties of these structures far awayfrom what bulk boron is like --- for example, bulk boron is aninsulator whereas many boron nanostructures should be robut metals; orall three-dimensional boron structures have the atoms bonding withicosahedral motifs, whereas boron nanostructures have primarilytwo-dimensional bonding gemetries featuring triangular and hexagonalbonding motifs. The intellectual output of this project has been toclarify how the properties of boron nanostructures depend on the size,bonding topolgy, and metal content, and which structures are the moststable and why. This knowledge helps furture studies on boronnanosystems and may also steer their potential applications asnanomaterials. The broader outcomes of this work have been manifold. First, agraduate student earned his Ph.D. doing this work and thus bothcontributed to advancing scientific knowledge at large and gained theanalytical and scientific skills to address future scientific ortechnological problems. Second, the scientific findings werepresented at multiple international meetings and published inhigh-quality journals to make researchers in the field aware of theresults and help progress the general field of nanoscience. Third, anundergraduate student was trained for a full calendar year and learnedthe basics of materials and computer simulations, and decided topursue the computational angle in graduate school. Fourth, a localhigh school teacher worked together with the principal investigatorfor over two years, and together they designed a set of web pages andphysical demonstration kits to explain the fundamentals of materialsphysics and chemistry to high-school students in the guise ofexplaining the operation of everyday electronic devices (hard drives,DVD/CD players, LEDs, lasers, transistors, etc.) Fifth, the highschool teacher and principal investigator presented a workshop basedon their work open to local New Haven science teachers: they explainedand demonstrated their kits, the web pages, and related science tohelp disseminate this knowledge and help these teachers better teachscience to high-school students.
