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MM: Fachverband Metall- und Materialphysik
MM 21: Transport - Ions and Electrons
MM 21.2: Vortrag
Dienstag, 17. März 2020, 10:30–10:45, IFW B
Quantum Paracrystalline Shear Modes in Metals — •Jun Yong Khoo1, Falko Pientka1, Po-Yao Chang1,2, and Inti Sodemann1 — 1Max-Planck Institute for the Physics of Complex Systems, D-01187 Dresden, Germany — 2Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
Unlike classical fluids, a quantum Fermi liquid can support a long-lived and propagating shear sound wave, reminiscent of the transverse sound in crystals, despite lacking any form of long-range crystalline order. This mode is expected to be present in moderately interacting metals where the quasiparticle mass is renormalised to be more than twice the bare mass, but, it is hard to excite and detect because it does not involve charge density fluctuations, in contrast to the conventional plasma mode. In this work we propose a strategy to excite and detect this unconventional mode in clean metallic channels. We show that the shear sound is responsible for the appearance of sharp dips in the AC conductance of narrow channels at frequencies matching the shear sound dispersion. The liquid resonates while minimizing its dissipation, a behavior characteristic of the sliding crystal. Ultra-clean 2D materials such as graphene, PdCoO2, and MgZnO/ZnO 2DEGs are therefore particularly promising platforms to discover the shear sound.