Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 10: Correlated Electrons: Other Theoretical Topics
TT 10.5: Talk
Monday, March 9, 2026, 12:00–12:15, HSZ/0103
Conformal elastic zero modes at isostructural transitions — •Lars Franke1, Nick Sander1, and Markus Garst1,2 — 1Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany — 2Institute for Quantum Materials and Technology, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
In correlated materials the coupling of the itinerant electrons to the crystal lattice can induce an isostructural instability where the bulk modulus vanishes. This occurs for example at the endpoint of a line of first order Mott metal-insulator transitions or metamagnetic transitions [1]. Interestingly, at such an isostructural instability the acoustic phonons remain non-critical and their velocities are finite. Consequently, the isostructural transition is a genuine mean-field transition without critical microscopic fluctuations. Nevertheless, we demonstrate that four elastic macroscopic zero modes exist. In addition to a soft mode given by a macroscopic volume change, there are three further zero modes corresponding to special conformal transformations. We discuss the consequences for the critical dynamics close to isostructural instabilities as well as realizations in dilational metamaterials.
[1] M. Zacharias, L. Bartosch, M. Garst, PRL 109 (2012) 176401