Heavy fermions constitute a large group of actinide- or rare earth-based alloys and compounds which exhibit a strong electronic mass renormalization at low temperatures as evidenced by 100-1000 enhanced thermodynamic and transport coefficients. There is no satisfactory understanding of the phenomenon.
A particularly interesting and important is a subset of these materials, non-fermi liquids. Non-fermi liquids violate some of the most fundamental principles of condensed matter physics derived from a fermi-liquid theory. Several phenomenological models have been proposed to account for exotic properties of non-fermi-liquids. These models can be divided into three categories; two-channel Kondo effect (Cox, Maple), quantum phase transition due to critical magnetic fluctuations (Tsvelik, Andraka), and Kondo disorder (MacLaughlin, Dobrosavljevic, Miranda, Andraka). Currently, there is no clear consensus as to the nature and microscopic origin of the phenomenon.
I synthesize samples using an inert atmosphere arc-melting or single-crystal flux-growth techniques. In-house experimental probes include: heat capacity, transport, and magnetization measurements in a wide range of temperatures and in magnetic fields to 16 T. Measurements at highest magnetic fields accessible are performed in National High Magnetic Field Laboratory, Tallahassee. Additional collaborative studies are carried out at PSI, Switzerland (µSR), Riverside (NMR), Oak Ridge (neutron diffraction) and Polish Academy of Sciences in Wroclaw (crystallography of new compounds and alloys).