Mark RzchowskiProfessor of Physics, University of Wisconsin-Madison
Research Area: Experimental Condensed Matter Physics
Specialty: Magnetic nanostructures, scanning probe spectroscopy
Postdoc: Harvard University Physics, 1988-1991
Ph.D Stanford University, 1988
A.B. Washington University in St. Louis, 1982
University of Wisconsin-Madison
1150 University Ave., Madison, WI 53706
Two-dimensional electron gases at oxide interfaces The interface between the perovskite oxide insulators SrTiO3 and LaAlO3 has recently been discovered to host a conducting gas of electrons localized to the interface. We investigate strong correlations in a smiliar electron gas by inserting a single rare-earth oxide monolayer into a SrTiO3 matrix. We find that the conductivity of this interface is determined by strong electron correlations, changing from conductor to insulator. More....
Domain walls in strongly correlated materials Walls between magnetic domains of different orientations have been investigated for many decades. The magnetic structure, the nanoscale size dependence, and electrical thermal scattering are reasonably well understood in many magnetic materials. But in strongly correlated systems, the magnetization gradient at the domain wall can alter the electronic structure of the material, for instance causing an insulating barrier to appear. More...
Ferroelectricity in ultrathin BaTiO3 Ultrathin ferroeelctric materials had long been thought to lose their polarization due to large energy cost of electric fields outside the materials. We measured BaTiO3 films as thin as 3.6 nm and found ferroelectric behavior. The presence of SrRuO3 top and bottom electrodes produces a depolarizing field that stabilizes the ferroelectricity. More...
MgB2: a two-band superconductor MgB2, a 40K superconductor discovered in 2001, has the unique honor of possessing two almost orthogonal bands that cross the Fermi surface, both of whose electrons become superconducting with different interaction strengths. This leads to two superconducting gaps, two different vortex core sizes, and two different band critical currents - essentially two distinct superconductors in the same spatial location. Low temperature scanning tunneling spectroscopy reveals the gap structure and the band symmetry. More...