Charge dynamics near the Mott transition of organic charge transfer salts κ-[(BEDT-TTF)_1-x (BEDT-STF)_x]₂Cu₂(CN)₃.

The quasi-2D organic charge transfer salt κ-[(BEDT-TTF)_1-x (BEDT-STF)_x] (abbr. κ-(STF) _x) is considered a model system to study bandwidth-tuned Mott metal-insulator transition (MIT) due to its simple electronic structure and the absence of competing charge or spin orders or structural transitions. While dielectric spectroscopy has provided evidence for the metal-insulator coexistence region, the associated domain dynamics near the Mott MIT remains to be investigated. Here, we study the charge dynamics in κ-(STF) _x by performing low-frequency (10^-5 Hz < f < 0.1 Hz) resistance noise measurements at temperatures T from 3 K to 140 K on samples with various substitutions through the Mott MIT. The preliminary results suggest that the noise power spectrum is ~1/f at all T. We will discuss several noise signatures, such as the T-dependence in different regimes and the effect of a magnetic field, as well as their possible implications.