Abstract:
In this talk, I will show that by controlling the distribution and type of defect on these hexagonal sp2-hybridized carbon sheets, one can modify their chemical, magnetic, electronic and mechanical properties that could lead to materials with novel applications. A classification of the various types of defects in graphene-like nanostructures is proposed and their properties will be presented based on first principles calculations: metallicity, half-metallicity, semiconductivity and magnetism. These modified properties illustrate some of the different characteristics that might result with controlled defect engineering. The classification of defects includes: a) edge effects of graphene nanoribbons and nanowiggles, b) the role of vacancies, c) the presence of topological defects, d) local changes in curvature, e) extended line of defects, and f) grain boundaries. The role of doping with foreign atoms will also be discussed and analyzed. In addition, the experimental efforts to generate, position and characterize these defects will be discussed, including chemical vapor deposition (CVD) on metal substrates, in-situ experiments with aberration corrected high-resolution electron microscopy (AC-HRTEM), scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). The combined experimental and theoretical approach shown here provides the basics to study defects in other atomic layered materials such as hexagonal boron nitride and metal chalcogenides (MoS2, WS2, etc.).

Biosketch:
Humberto Terrones obtained his PhD degree from Birkbeck College in 1992 (University of London). Following a postdoctoral stay at Cambridge University (UK), he joined the Institute of Physics at the National Autonomous University of Mexico (UNAM). After eight years, Humberto moved to IPICYT as Head of the Advanced Materials Department to work mainly in nanosciences and nanotechnology. He is presently visiting Professor at the Penn State University (USA) and at the Federal University of Ceara (Brazil). As a leading researcher with a long experience in nanostructured carbon materials, he has published more than 190 scientific papers in different aspects of nanostructures (synthesis, theory and characterization) and has over 8000 thousand citations. His "H" index is 51.