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06.14.12 News
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Picture of the Day

Dendrite

These images render electron flow paths in a "two dimensional electron gas." The research leading to the "Transport" series (of which Dendrite is a part) was inspired by the experiments of Mark Topinka, Brian Leroy, and professor Robert Westervelt at Harvard, which actually measured the paths taken by the electrons. The theory was performed with the help of Scot Shaw, a member of my research group at the time. Dendrite is based on flow patterns for electrons riding over bumpy landscape, which is what electrons experience in the two-dimensional electron gas (2DEG) that they dwell in. A 2DEG is a sea of electrons confined to a sheet, i.e. two dimensions. The bumps they encounter are due to charged atoms lying above the sheet. The electrons have more than enough energy to ride over any bump, and the concentrations of electron flow into the branches seen here are recently discovered indirect effects of that bumpy ride. The channeling or branching was unexpected and has implications for small electronic devices of the future. This image was made in a computer simulation by launching 100,000 electrons from the upper middle of the image, and following their tracks. Each electron had a slightly different launch angle. A color map was applied to turn the density of electron paths into color. A gradient fill was used in the region not traversed by any electron.
Image credit: Eric J. Heller, Harvard University