Join us May 18th for our Weekly Physics Colloquium! Guest Speaker, Dr. Scott Dietrich,will be joining us from the Department of Physics at Villanova University.

 

Many people consider electricity as flowing like water in a pipe, but this analogy breaks down when electrons interact strongly. The collective behavior of electrons is often more noteworthy than the sum of individuals – more is different. Exciting new electronic properties result when electrons interact strongly: they can crystallize, superconduct, coalesce, and more. At low temperatures and high magnetic fields, two-dimensional electron systems host a wide variety of electronic states that rapidly transition between solid, liquid and gas phases. The fractional quantum Hall states are one type of such liquid phases. These often compete with a solid phase driven by electron interactions, the electron crystal. In this colloquium, I will discuss the current experimental signatures of various electronic crystals in graphene then describe our efforts to detect and study these phases using spectroscopic techniques at microwave frequencies. The transmission of this radiation is sensitive to carrier conductivity and the collective oscillations of solid phases pinned to crystal impurities. Conductivity measurements provide some of the most accurate edgeless measurements of the fractional quantum Hall effect, while pinning resonances provide insight into the nature of these states and electron-electron interactions.

 

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