Description:

Over the past few decades, our view of metals has undergone a transformation. While conventional metals are understood within the paradigm of the Landau Fermi liquid theory, many metals of contemporary interest fall outside this umbrella. In this talk I will present our work on two oxide metals, LaNiO3 and SrTiO3-δ, whose carrier densities differ by more than five orders of magnitude. The perovskite rare-earth ReNiO3 nickelates have magnetic and metal-insulator transitions (MIT), which arise as a result of correlations between charge, lattice and spin degrees of freedom. LaNiO3 is the only member of this family that remains metallic and paramagnetic down to the lowest temperatures, though it has long been suspected of being a ‘strange’ metal. I will present our work on MBE grown thin films and heterostructures of LaNiO3, where we show that LaNiO3 is on the verge of a magnetic instability, and in fact is a quantum critical metal at the lowest temperatures. These results are discussed in analogy with heavy fermions. I will also discuss our recent results on transport in another unconventional metal, very dilutely doped reduced SrTiO3-δ, where we focus on superconductivity deep in the anti-adiabatic limit - at carrier densities even lower than in elemental Bi.

Dr. Anand Bhattacharya, Argonne National Laboratory

Host: Jens Koch

Keywords: Physics, Astronomy, Condensed Matter