Dresden 2009 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 1: Focussed Session: The Mott Transition in Model Systems

TT 1.5: Topical Talk

Montag, 23. März 2009, 12:30–13:00, HSZ 03

Lattice Effects in Strongly Correlated π-electron Systems Close to the Mott Transition — •M. de Souza¹, A. Bruehl¹, C. Strack¹, B. Wolf¹, R.S. Manna¹, J.A. Schlueter², D. Schweitzer³, and M. Lang¹ — ¹Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Str. 1, SFB/TRR49, D-60438 Frankfurt (M), Germany — ²Chem. and Mat. Science Divisions, Argonne NL, Argonne, IL 60439, USA — ³Physikalisches Inst., Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany

Organic charge-transfer salts have been recognized as model systems for studying the interplay of strong electronic correlations and low dimensionality. Depending on the chemical composition and/or hydrostatic pressure, the materials show a rich variety of electronic phases including Mott insulating, spin- and charge-ordered, anomalous metallic, spin-liquid-like as well as superconducting states. By using ultrahigh-resolution thermal expansion measurements, we have explored the role of the lattice degrees of freedom for some of the above-mentioned phases. We will discuss the Mott transition in κ-(D8-BEDT-TTF)₂Cu[N(CN)₂]Br [1], the mysterious charge-order transition coinciding with ferroelectric order in (TMTTF)₂X [2] as well as the spin-liquid-like properties observed for κ-(BEDT-TTF)₂Cu₂(CN)₃ [3]. Our results highlight the intricate role of the lattice degrees of freedom for stabilizing the various ground states in these materials.

[1] M. de Souza et al., Phys. Rev. Lett. 99, 037003 (2007).

[2] M. de Souza et al., Phys. Rev. Lett. 101, 216403 (2008).

[3] S. Yamashita et al., Nature Phys. 4, 459 (2008).