Dresden 2017 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 1: Focus Session: Frustration in Mott Insulators and Mott Criticality
TT 1.4: Hauptvortrag
Montag, 20. März 2017, 11:15–11:45, HSZ 03
Breakdown of Hooke’s Law of Elasticity at the Mott Critical Endpoint in an Organic Conductor — •Elena Gati1, M. Garst2,3, R.S. Manna1, U. Tutsch1, B. Wolf1, L. Bartosch4, T. Sasaki5, H. Schubert1, J.A. Schlueter6, and M. Lang1 — 1Physikalisches Inst., Goethe Univ., SFB/TR49, Frankfurt, DE — 2Inst. f. Theo. Physik, Univ. zu Köln, DE — 3Inst. f. Theo. Physik, TU Dresden, DE — 4Inst. f. Theo. Physik, Goethe Univ., FFM, DE — 5IMR, Tohoku Univ., Sendai, Japan — 6NSF, Arlington, USA
The Mott transition is a prime example of the manifestation of strong electron correlations in solids. Despite its importance for a wide range of materials, however, fundamental properties, such as the universal critical behavior, remain unresolved. An essential, experimentally yet unexplored aspect is the role of electron-lattice coupling on the criticality. In this talk, we will present measurements of the thermal expansion as a function of pressure, P, around the P-induced Mott transition in the organic charge-transfer salt κ-(BEDT-TTF)2Cu[N(CN)2]Cl [1]. We observe a breakdown of Hooke’s law of elasticity upon approaching the critical endpoint, revealing an intimate, non-pertubative coupling of the critical electronic degrees of freedom to the crystal lattice. Our results are fully consistent with mean-field (MF) criticality, predicted theoretically for electrons in a compressible lattice with finite shear modulus [2]. We argue that every pressure-tunable Mott transition shows the universal properties of an isostructural solid-solid endpoint with MF criticality rather than a liquid-gas endpoint.
[1] Gati et al., Sci. Adv., submitted;
[2] Zacharias et al., PRL 109, 176401 (12).