SEMINAR:Universal Planckian resistivity from coherent charge carrier..

Speaker:Alhun Aydin, Koc University and Harvard University

Title: Universal Planckian resistivity from coherent charge carrier-lattice vibration dynamics

Date/Time:12 April 2023 / 13:40 - 14:30

Location: FENS G032 (Hybrid)

Zoom Link:https://sabanciuniv.zoom.us/j/96558816752?pwd=eE9yRHhCUTl3cXRCNzNtelQ4bWxadz09

Meeting ID: 965 5881 6752

Password: 295858

Abstract:Strange metals exhibit universal T-linear resistivity described by the Planckian scattering rate, the origin of which is not understood. It was thought that phonons were disqualified as prime agents, despite their predominance in other resistivity contexts. The problem seems to have been not with phonons, but with how they were treated. We show that Planckian resistivity can in fact emerge from the nonperturbative scattering dynamics of thermal lattice vibrations and coherent charge carriers by a wave-on-wave approach that we developed. This becomes apparent when describing the lattice vibrations in the coherent state representation, and treating charge carriers as quantum wave packets scattering from the resulting dynamic disorder field formed by lattice vibrations, the deformation potential. Under this coherent and nonperturbative scattering dynamics, we find that carrier velocities are suppressed, the quasiparticle picture breaks down and a new phase called the vibronic fluid emerges. A competition between the static and dynamic aspects of the random acoustic deformation potential is set up, leading to a previously conjectured quantum bound of diffusion with universal properties. We successfully obtain the T-linear resistivity of three different strange metals using their experimental parameters in our numerical simulations. We also provide an explanation for the underlying mechanism of the Planckian scattering based on the phenomenological model of Thouless scaling theory. Furthermore, we provide explanations for the violation of the Mott-Ioffe-Regel limit as well as the emergence of the displaced Drude peak in strange metals. 

Bio:Alhun Aydin is a physicist, currently holding a joint postdoctoral position at the Physics Departments of Harvard University and Koç University. He obtained his BSc in Physics at Koç University and his MSc and PhD at Istanbul Technical University, Energy Institute. During his doctoral studies, he spent a year as a visiting researcher at Uppsala University, Physics Department, and at the Hebrew University of Jerusalem, Fritz Haber Center for Molecular Dynamics. In his award-winning PhD thesis, he predicted the existence of a new effect appearing at the nanoscale, so-called the quantum shape effect, and explored its novel thermodynamic implications and energy applications. In his postdoctoral research, he worked on the development of a new framework to study the charge carrier-lattice vibration dynamics in condensed matter systems coherently and nonperturbatively. This work with its ongoing extensions may lead to a possible solution for the strange metal properties of high-temperature superconductors. Presently, his research is focused on three main areas: theory of quantum materials, quantum thermodynamics&transport and novel nanoscale energy devices.