Nanoenergetics - Energy processes at nanoscale
Energy transfer at interfaces
Interfaces are of extreme importance in energy transfer processes. While these processes are usually well captured through using continuum models such as Fourier's law, Newtonian and Maxwell equations in bulk materials, the interfaces are much more difficult to handle. Especially at the nanoscale, interfacial properties play the same dominance as the bulk ones. Some nanoscale devices are even interfaces themselved (e.g. molecular junctions). Lacking of consistent theories for these problems forces us to utilize intensive computer simulation techniques, from the first principles such as the Schroedinger, Newtonian equations and fundamental physical constants.
Figure 1 Interfacial coupling between a graphene sheet and metal substrates
Energy dissipation in nano-devices
One of the original aims of the nanotechnology, as visioned by Feynman half a century ago, is to minimize device dimensions to the atomic level. The benefits are figures of merits such as ballistic electron and phonon transport, abilities of quantum information processing, and the cost is that there is extremely high energy localization in the device and its dissipation into heat may eventually lead to failure. Our mission is to understand the energy dissipation process and engineer it.
Figure 2 High energy density and dissipation is the key obstacle to nanoelectromechanical devices.
ReferencesXu and Buehler, (2010)
Xu and Buehler, Nano Letters, ACS Nano, Nanotechnology (2009)
Xu et al., Nano Research, Nanotechnology, J. Comp. Theo. Nanosci. (2008)
Xu et al., Physical Review B, Applied Physics Letters (2007)
Zhao et al., Nanotechnology, J. Comp. Theo. Nanosci. (2006)