Dresden 2009 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 1: Focussed Session: The Mott Transition in Model Systems
TT 1.5: Topical Talk
Monday, March 23, 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).