Cottrell College Science Awards - 2015
Quantum Hall Effects in Hybrid Graphene
In 1879 Edwin Hall discovered that if he applied a magnetic field to a strip of thin, gold foil conducting electricity, it produced a tiny voltage difference on either side of the strip.
Since then the Hall effect has been put to work in many kinds of sensors, from speedometers to compasses but more significantly for science, 20th-century researchers pursued its ramifications into the quantum realm, where they discovered electrons ordering themselves in new ways as conductors were thinned down to the atomic scale. The pursuit of ever thinner conductors led not only to the discovery of the quantum Hall effect, but to faster, more efficient computer chips and photovoltaic solar cells, among other modern marvels.
Now Paul Cadden-Zimansky, assistant professor of physics at Bard College, has received a Cottrell College Science Award from Research Corporation for Science Advancement to look for new quantum Hall effects in hybrid graphene crystals, the world’s thinnest material. These crystals are one-, two- and three-layer stacks of atoms supercooled to make the precise measurement of electrons possible.
Specifically, Cadden-Zimansky and his students will be looking for new “topological orders” among those electrons – new electronic states of matter. While modern technology rests on cleverly combining the three basic types of electronic materials – conductors, semiconductors, and insulators – Cadden-Zimansky and his students will use the quantum Hall effect to look for new classes of "topological states" formed by the electrons in graphene. These electronic states are distinct from those found in the three types of conventional materials; Cadden-Zimansky’s work could tell us more about what’s behind them.
To observe novel quantum Hall states in the test materials they will make annual trips to the National High Magnetic Field Lab to use the most powerful electromagnets available.