When structures are shrunk to the nanometer length scale, their bulk properties often become ill-defined and novel wave behaviors can emerge. For example, in a 3D crystal lattice vibrations are perturbatively small, yet in a 1D molecule like a carbon nanotube (CNT), transverse thermal vibrations can have amplitudes that far exceed the CNT’s diameter. These large amplitude vibrations lead to new emergent physics, and in this seminar I will discuss our work in which we directly measure CNT’s motion in real time and see how energy flows among resonant modes in a unique way.

As another example of nanoscale emergent wave phenomena, electrons in a flake of graphene propagate as coherent waves, rather than scattering frequently as they do in a bulk metal. We harness this behavior to build “electron optics labs” in which we create collimated beams controlled via magnetic fields and electrostatic gates. With these devices we are able to directly observe electron interference as well as Klein-tunneling—quantitatively observing how electrons can tunnel through an arbitrary barrier with perfect transmission.

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Arthur Barnard is a Postdoctoral Fellow in the Department of Physics at Stanford University. He received his BS, MS and PhD in Applied and Engineering Physics at Cornell University. Arthur is particularly interested in experimentally probing emergent physical phenomena at the nanoscale using novel scanned probe and nanolithography techniques