CMT Seminar: Probing metal-insulator transitions with Quantum Monte Carlo Simulations
Monday, November 21, 2011 – 3:15pm
Instituto de Fisica, Universidade Federal do Rio de Janeiro
Metal-insulator transitions are a topic of intense activity. From the experimental point of view, one clear signature of the insulating state is a vanishing conductivity as the temperature is decreased. However, from the theoretical point of view, and in the context of quantum Monte Carlo simulations in particular, detecting an insulating state is not always straightforward. Here I will discuss the behavior of the dc-conductivity, compressibility and Drude weight as probes to density-driven metal-insulator transition in the Hubbard model on a square lattice. The compressibility and the dc-conductivity are known to suffer from “closed-shell” effects, due to the presence of artificial gaps in the spectrum, caused by the finiteness of the lattice. The Drude weight, on the other hand, is not too sensitive to finite-size effects, being much more reliable as a probe to an insulating state.
Host: Marcos Rigol