Quasiparticles at the verge of localization near the Mott metal-insulator transition in a two-dimensional material.
The dynamics of charge carriers close to the Mott transition is explored theoretically and experimentally in the quasi-two-dimensional organic charge-transfer salt, kappa-(BEDT-TTF)_(2)Cu[N(CN)_(2)]Br_(x)Cl_(1-x), with varying Br content. The frequency dependence of the conductivity deviates significantly from simple Drude model behavior: there is a strong redistribution of spectral weight as the Mott transition is approached and with temperature. The effective mass of the quasiparticles increases considerably when coming close to the insulating phase. A dynamical mean-field-theory treatment of the relevant Hubbard model gives good quantitative description of experimental data.
Merino
J
J
Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Madrid 28049, Spain.
Dumm
M
M
Drichko
N
N
Dressel
M
M
McKenzie
Ross H
RH