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Non-Abelian Phases in the Fractional Quantum Hall Regime

The fractional quantum Hall effect (FQHE) occurs in a two-dimensional electron gas (2DEG) subjected to a perpendicular magnetic field at low temperature. It is now understood to arise from strong electron-electron interactions. In transport experiments the FHQE is characterized by Hall resistance quantized to rational fractional values of h/e2 and vanishingly small longitudinal resistance. Quasi-particle excitations in the FQHE are called anyons.

Ultra-High Mobility 2DEGs and 2DHSs in GaAs Grown by Molecular Beam Epitaxy

A major thrust in the Quantum Semiconductor Systems group is growth of extremely high quality GaAs/AlGaAs heterostructures. One metric of quality is 2D mobility, which can now exceed 30 x 106 cm2/Vs at low temperatures. At low temperature mobility is limited by imperfections in the grown sample. Imperfections include intentionally introduced charged impurities, unintentional background charged impurities and structural defects.

Our efforts are focused in 3 areas: improved MBE vacuum conditions, source material purity, and heterostructure design.

Novel Devices with Non-Polar m-plane GaN/AlGaN and Lattice-Matched AlInN/GaN heterostructures

Our work in the III-Nitride material system is focused on exploiting its unique physical properties to produce novel light sources based on intersubband transitions. Due to the large conduction band offsets available in Al(In)GaN/GaN heterostructures, intersubband transitions can span the technologically important near-IR (~1.5microns) to far-IR (~100microns) spectral range.

Prof. Michael J. Manfra

Bill and Dee O’Brian Chair Professor of Physics and Astronomy, Purdue University Professor of Electrical and Computer Engineering, Purdue University Professor of Materials Engineering, Purdue University PhD, Physics, Boston University, 1999 A.B. Cum Laude in Physics, Harvard University, 1992 Email: mmanfra@purdue.edu Office: Room 84 (Physics) Room 1250 (Birck) Phone numbers: 765-494-3016 (Physics) 765-496-7703 (Birck) Professor […]

Dr. Geoff Gardner

Research Associate, Microsoft Corporation Visiting Scholar, Purdue University E-mail: geoff@purdue.edu Dr. Gardner began working in Prof. Manfra’s research program in 2009, and is now part of Station Q Purdue.  He is a native Boilermaker receiving a B.Sc., M.Sc. and PhD in applied physics, physics and materials engineering respectively at Purdue University.  Previously, Geoff served as […]

Dr. Anthony Hatke

Postdoctoral Research Associate PhD, University of Minnesota – Twin Cities, 2012 E-mail: hatke@purdue.edu Dr. Hatke received his PhD from the University of Minnesota in 2012 where his focus was on low temperature magnetotransport of high mobility GaAs quantum wells driven out of equilibrium with his thesis advisor Michael Zudov. After obtaining his PhD he accepted […]

Dr. Sergei Gronin

Dr. Sergei Gronin obtained his PhD from the Ioffe Institute of Saint-Petersburg, Russia, developing MBE grown of low threshold lasers based on II-VI materials for green and yellow spectral region.  Prior to joining Professor Manfra’s group as part of Microsoft Station Q Purdue in May, 2017 he was a Junior Researcher in the Laboratory of Quantum-size […]

Dr. Raymond Kallaher

Dr. Kallaher received his PhD from Florida State University in 2007, studying the ferromagnetic semiconductor europium sulfide. Prior to joining Professor Manfra’s group as part of Microsoft Station Q Purdue in 2017, Dr. Kallaher was a Senior Scientist at Modern Microsystems working on process development for fabricating high power electronic devices and x-ray optics. He […]