David Cobden               Nanodevice Physics

Professor Cobden's group studies the physics of individual nanotubes and nanowires of various materials, using a combination of electrical transport (down to liquid helium temperatures), optical, and scanning probe microscopy. We aim to explore new physical phenomena, from the esoteric to the practical, relevant on the nanoscale. Some examples of electronic phenomena we have studied in carbon nanotubes are the Luttinger liquid, the Fermi-edge singularity, conductance quantization, the non-equilibrium Kondo effect, and charge pumping. Recently we have become interested in phase transition phenomena in small system. One of our projects, in collaboration with Prof. Oscar Vilches, uses a suspended carbon nanotube as vibrating "yoctobalance", with single-atom sensitivity, to detect phase transitions in cylindrical gas monolayers adsorbed on its surface. Another investigates metal-insulator transitions in nanoscale crystals of vanadium oxides.

Assistant Professor Fu's (joint faculty in EE) experimental research focuses on spin-systems in solids for quantum information processing (QIP) and sensing applications.  Of particular interest are materials in which the spins can be optically accessed to enable spin initialization, coherent spin manipulation, and optical spin state measurements.  Optical spectroscopic techniques including pump-probe, optical spin-echo, and high-resolution spectroscopy are used to further understand spin dynamics.  Coupled optical-spin systems are integrated into nanophotonic devices in order to enable optical communications between spins for QIP and to increase magnetic sensitivity in sensing applications.   Spin systems currently studied in the group include semiconductor impurities, semiconductor quantum dots, and color centers in diamond.

Professor Olmstead's group focuses on the growth and characterization of semiconductor nanostructures that combine a silicon substrate with nanoscale layers of materials with properties complementary to silicon, such as magnetism or light emission. The incorporation of such structures into emerging technologies is hampered by lack of knowledge about both their formation and their resultant properties. Her research makes use of molecular beam epitaxy with in situ scanning probe microscopy and photoelectron spectroscopy, supplemented by ex situ structural, magnetic, optical and electrical measurements. Among other systems, this research group is collaborating with Prof. Ohuchi of the UW Materials Science Department on studies of nanoscale films of chalcogenide semiconductors on silicon, which have possible applications in nonvolatile memory devices.

Professor Seidler's research focuses on the development and application of novel x-ray spectroscopies to problems of basic, industrial, and environmental interest. To this end, the group has constructed and commissioned the Lower Energy Resolution Inelastic X-ray scattering (LERIX) spectrometer, now permanently located at the Advanced Photon Source x-ray synchrotron at Argonne National Laboratory. In the next five years, this research will continue to emphasize investigation of nano- and bulk-phase systems relevant for clean energy and also on basic questions involving correlated electron phenomenon in f-electron systems. The group members work closely with John Rehr's theory group, and the groups' students often have theory side-projects en route to their dissertation. Prof. Seidler is also collaborating on a project to broadly improve x-ray protein crystallography through better understanding and manipulation of radiation damage from photoelectron processes.

Assistant Professor Wiggins (joint faculty in Bioengineering) is working on biophysics and quantitative cell biology. Far from being well-mixed, almost all biological systems exhibit precise spatial and temporal control of protein, mRNA, and DNA concentration, demonstrating that cells measure distance and detect proximity with a molecular-scale tool kit. Although these phenomena have traditionally been studied in the context of detailed expression patterning in development, recent exciting results (including our own work) reveal that precise spatial organization is the rule rather than the exception in the bacterial cell. Prokaryotic cells develop cell polarity, exhibit time-dependent gradients of protein concentration, can divide with astonishingly high-precision at midcell, and exhibit precise control over the spatial position of genetic loci in the cell. Our lab is working to understand these organizational phenomena using techniques ranging from genetics and traditional cell biology to next generation sequencing and single molecule fluorescence experiments.

Assistant Professor Xiaodong Xu's (joint faculty in MSE) group investigates new physics arising in various solid state nanostructures. The work involves nanomaterial synthesis, device fabrication, optical spectroscopy, and transport measurements.  Currently his group is working on the following topics: high quality graphene growth with grain and layer thickness control; investigation of the electronic, thermal, and optoelectronic properties of graphene and its integration of other nanophotonic systems; nonlinear optical spectroscopy of bilayer graphene with a tunable electronic bandgap; optical probing of a new phase of matter - topological insulator; ultrafast spectroscopy; and scanning photocurrent microscopy of strong correlated materials (in collaboration with Prof. Cobden's group).
 

Jens Gundlach           Nanopores
 

Oscar Vilches             Low Temperature Physics
 

Larry Sorensen          Neural Physics