Our guest on November 17 was Dr. Jernej Mravlje from “Jozef Stefan” Institute, Ljubljana, Slovenia. Dr. Mravlje held SCL seminar of the Center for the Study of Complex Systems, in the library reading room “Dr. Dragan Popović” of the Institute of Physics Belgrade. The talk eas entitled: “DMFT insights to incoherent transport in strongly correlated metals”
The electronic transport is one of the most poorly understood aspects of strongly correlated electron systems. The resistivity is often found at large temperatures to exceed the Mott-Ioffe-Regel (MIR) value that corresponds to a scattering event every lattice spacing. This bad-metallic behavior that cannot be understood in terms of Boltzmann
quasiparticle transport is currently explored by several different theoretical approaches.
We investigated this regime for a doped Mott insulator using the dynamical mean-field theory (DMFT) and high-temperature expansion approaches. The DMFT equations are solved using the state-of-the art quantum-Monte-Carlo and numerical renormalization group methods and consistency between the obtained results demonstrates their accuracy. Along resistivity we calculated also the single-particle spectral functions and the charge compressibility. When resistivity exceeds the MIR value, the quasiparticles melt and one enters into a regime in which the scattering rate (diffusion constant) saturate and the carrier density (charge compressibility) drops as 1/temperature. In this regime (in which resistivity is linear in
temperature), the bad-metal is somewhat similar to a doped semiconductor dominated by the temperature evolution of the carrier number rather than the scattering. We will discuss the relevance of the results for the behavior found in real materials and optical lattices and compare them against other theoretical approaches.