Zettl Research Group
In solid state physics, material properties often change with respect to intensive physical quantities, such as temperature, pressure, magnetic field, etc. How they change often reveal the nature of the electronic ground state, interactions between phonons and electrons, effects of impurities and much more that we want to know to understand the physics of a particular material or a class of materials.
In the Zettl lab we have laboratory setups to change several of the intensive quantities mentioned above that are considered relevant in most solid state systems. Resistance and magnetic susceptibility vs. temperature measurements are routinely performed to characterize new materials. There are two kinds of pressure cells in the lab where the transport properties can be measured under hydrostatic conditions up to hundreds of thousands of kilobars. And the two superconducting magnets can sometimes significantly change how a material behaves by generating fields up to 17 Tesla.
Among the large number of materials that can be studied and whose potentially interesting properties may be discovered by varying one or more of the physical quantities mentioned above are carbon nanotubes, boron nitride (BN) nanotubes, nanotube peapods, the element Si, the charge density wave material blue bronze (K0.3MoO3), high-temperature superconductors and the giant magnetoresistance oxides, just to name a few.
At the moment, we are studying MgB2 and its variants after doping, using these techniques. MgB2 is an interesting superconducting material both because it has the highest transition temperature outside of the HTSC family and because of the unusual 2-gap nature.