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Bandwidth-controlled Mott transition in kappa-(BEDT-TTF)2Cu[N(CN)2]Br{x}Cl{1-x}: Optical studies of correlated carriers
- Source :
- Phys. Rev. B 79, 195106 (2009)
- Publication Year :
- 2009
-
Abstract
- In the two-dimensional organic charge-transfer salts kappa-(BEDT-TTF)2Cu[N(CN)2]Br{x}Cl{1-x} a systematic variation of the Br content from x = 0 to 0.9 allows us to tune the Mott transition by increasing the bandwidth. At temperatures below 50 K, an energy gap develops in the Cl-rich samples and grows to approximately 1000 cm-1 for T -> 0. With increasing Br concentration spectral weight shifts into the gap region and eventually fills it up completely. As the samples with x = 0.73, 0.85 and 0.9 become metallic at low temperatures, a Drude-like response develops due to the coherent quasiparticles. Here, the quasiparticle scattering rate shows a omega^2 dependence and the effective mass of the carriers is enhanced in agreement with the predictions for a Fermi liquid. These typical signatures of strong electron-electron interactions are more pronounced for compositions close to the critical value x_c \approx 0.7 where the metal-to-insulator transition occurs.<br />Comment: 11 pages, 12 figures
- Subjects :
- Condensed Matter - Strongly Correlated Electrons
Subjects
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. B 79, 195106 (2009)
- Publication Type :
- Report
- Accession number :
- edsarx.0903.0244
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevB.79.195106