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Department of Physics525 Northwestern Avenue
West Lafayette, IN
47907-2036
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Jian Huang
Wayne State University
"Into the flat land: Transport studies of ultra-dilute GaAs two-dimensional hole systems"
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Friday February 15, 2013
3:30pm PHYS 203
Refreshments are served at 3:00 p.m. in Physics room 242.
http://physics.clas.wayne.edu/faculty/profile.php?id=77689Low temperature charge transport studies of high purity electron systems encompass fundamental subjects of disorder and electron-electron interaction. 50 years after Anderson's theory of localization for non-interacting electrons, the question on whether and how electron-electron interaction qualitatively alters the picture is still unsettled. Fascinating subjects on interaction-driven phenomena such as Wigner crystallization of electrons (for the quantum scenario) have never been demonstrated. Experimentally, high-purity semiconductor bulk materials offer a desirable tunability of charge density down to ultra-dilute limits where both new frontiers of physics and important applications such as quantum information technologies can be explored. However, such a transition is often overshadowed by the substantial disorder which competes with or even dominates over interaction by rendering the system into an Anderson insulator. We report findings obtained through measuring ultra-high-purity GaAs two-dimensional hole systems with dilute charge concentrations down to . The measurement of the charge density and temperature dependence of the conductivity provides evidence for the interaction-driven many-body characteristics in contrast to the disorder-dominated situations. Moreover, some striking discontinuous behaviors observed for charge densities below suggest a possible phase transition which will be discussed.