Regensburg 2016 – scientific programme
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DS: Fachverband Dünne Schichten
DS 49: Transport: Molecular Electronics and Photonics II
(Joint session of CPP, DS, HL, MA, O and TT, organized by TT)
DS 49.4: Talk
Thursday, March 10, 2016, 15:45–16:00, H23
Experimental investigation of the role of electron-phonon-coupling on the Mott critical behavior in the organic charge-transfer salts κ-(BEDT-TTF)2X — •E. Gati1, M. Garst2, R.S. Manna1, U. Tutsch1, B. Wolf1, S. Hartmann1, L. Bartosch3, T. Sasaki4, H. Schubert1, J.A. Schlueter5, and M. Lang1 — 1Physikalisches Inst., Goethe Uni, SFB/TR49, Frankfurt, DE — 2Inst. f. Theo. Physik, Universität zu Köln, DE — 3Inst. f. Theo. Physik, Goethe Uni, FfM, DE — 4IMR, Tohoku University, Sendai, Japan — 5Materials Science Division, Argonne National Laboratory, USA
The Mott transition is one of the key phenomena of strongly correlated electron systems. Of fundamental interest is the determination of its critical behavior and the underlying universality class. Despite intensive experimental efforts, the universality class is still unresolved. A key aspect, which has not been addressed in these approaches, is the role of electron-phonon-coupling as it is supposed to alter the critical properties to Landau criticality [1]. We will present thermal expansion studies under pressure [2] on the organic charger-transfer salt κ-(BEDT-TTF)2Cu[N(CN)2]Cl. This technique is a very sensitive tool to detect critical behavior [3] as well as influences of the lattice on the electronic subsystem [1]. Our results clearly show a breakdown of Hooke’s law of elasticity which is a direct evidence for significant electron-phonon-coupling. Furthermore, we will discuss its effect on the critical exponents determined by this thermodynamic probe.
[1] Zacharias et al., PRL 109, 176401 (12)
[2] Manna et al., Rev. Sci. Instrum. 83, 085111 (2012)
[3] de Souza et al., PRL 99, 0370031 (2007)