Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 38: Correlated Electrons: Metal-Insulator Transition 1

TT 38.14: Vortrag

Mittwoch, 13. März 2013, 13:00–13:15, H20

Mott Metal-Insulator Transition on Compressible Lattices — •Mario Zacharias¹, Markus Garst¹, and Lorenz Bartosch² — ¹Institut für Theoretische Physik, Universität zu Köln — ²Institut für Theoretische Physik, Goethe-Universität, Frankfurt a. M.

In the presence of a coupling to the crystal lattice, the critical properties of the finite temperature Mott end point are drastically altered. While the incompressible Mott transition is analogous to the liquid-gas transition, the compressible Mott transition is a solid-solid transition. Similar as for critical ferroelectrics, the Ising criticality of the electronic system is preempted by an isostructural instability. Long-range shear forces suppress microscopic fluctuations and, thus, the end point is governed by Landau criticality. A hallmark of this effect is the breakdown of Hooke’s law of elasticity, i.e. a non-linear strain-stress relation characterized by a mean-field exponent. For the Mott end point of κ-(BEDT-TTF)₂X, we predict critical elasticity to dominate in a temperature range Δ T^* ≃ 2.5 K and over a pressure region of Δ p ≃ 50 bar around the end point.