Materials and Devices at the Atomic Scale

When: Friday, September 06, 2013 at 4:00 pm
Where: DA 118
Speaker: Dr. Wei Li Wang
Organization: Kaxiras Research Group and Westervelt Research Group, Department of Physics and School of Engineering and Applied Sciences, and Harvard University
Sponsor: Nanophysics Seminar

The atomic scale is the ultimate frontier of nano science and technology. Material and device properties do not simply scale linearly to the atomic scale; new chemistry and physics emerge when reaching the scale of nature’s basic building blocks [1-4]. Recent advances in microscopy and computing power make it possible not only to visualize and understand atomic systems but also to explore novel solutions to some key problems that we are facing in electronics, biology, and clean energy applications. In this talk, I will discuss an approach that combines in situ high-resolution transmission electronic microscopy (HRTEM) and first-principles calculations. I will show the first observed dynamics of a single Si atom chiseling atomic structures in single-layer graphene [1]. The resultant atomic structures can potentially be used for single-biomolecule sensing and for exploring new electronics/spintronics paradigms [3, 4].

1. W. L. Wang, E.G.D. Santos, B. Jiang, E.D. Cubuk, A. Centeno, A. Pesquera, A. Zurutuza, J. Ciston, R. Westervelt, E. Kaxiras. A single-atom chisel for sculpting atomic structures in graphene. Submitted.

2. W. L. Wang, B. Sagar, W. Yi, D. Bell, R. Westervelt, and E. Kaxiras. Direct imaging of atomic-scale ripples in few layer graphene. Nano Letters 8: 2278, 2012.

3. W. L. Wang, O.V. Yazyev, S. Meng, and E. Kaxiras. Topological Frustration in Graphene Nanoflakes: Magnetic Order and Spin Logic Devices. Physical Review Letters 102: 4, 2009.

4. W. L. Wang, S. Meng, E. Kaxiras. Graphene nanoflakes with large spin. Nano Letters 8: 241, 2008.

 

Dr. Wei Li Wang obtained his Ph.D. degree in Mechanical Engineering from the University of Michigan with research on applications and imaging mechanisms of Scanning Probe Microscopy. He then studied physics at Harvard University (MS 2006), followed by post-doc work jointly in the Kaxiras Group (theory) and the Westervelt Group (experiment), where he developed a research approach combining high resolution imaging/fabrication and first-principles calculations. Since 2011, Dr. Wang has been regularly traveling to the National Center of Electron Microscopy of Lawrence Berkeley National Lab, conducting experiments on graphene with the TEAM 0.5 and TEAM I. His current research focus is on the interplay between electrons, photons and phonons at the atomic scale and its applications in nano-electronics/spintronics, biosensing, and energy materials.

Host: Assistant Professor Swastik Kar