Investigation of Planckian behavior in a high-conductivity oxide: PdCrO2

Elina Zhakina, Ramzy Daou, Antoine Maignan, Philippa H. McGuinness, Markus König, Helge Rosner, Seo Jin Kim, Seunghyun Khim, Romain Grasset, Marcin Konczykowski, Evyatar Tulipman, Juan Felipe Mendez-Valderrama, Debanjan Chowdhury, Erez Berg, Andrew P. Mackenzie

Research output: Contribution to journalArticlepeer-review

Abstract

The layered delafossite metal PdCrO2 is a natural heterostructure of highly conductive Pd layers Kondo coupled to localized spins in the adjacent Mott insulating CrO2 layers. At high temperatures, T, it has a T-linear resistivity which is not seen in the isostructural but nonmagnetic PdCoO2. The strength of the Kondo coupling is known, as-grown crystals are extremely high purity and the Fermi surface is both very simple and experimentally known. It is therefore an ideal material platform in which to investigate “Planckian metal” physics. We do this by means of controlled introduction of point disorder, measurement of the thermal conductivity and Lorenz ratio, and studying the sources of its high-temperature entropy. The T-linear resistivity is seen to be due mainly to elastic scattering and to arise from a sum of several scattering mechanisms. Remarkably, this sum leads to a scattering rate within 10% of the Planckian value of kBT/ℏ.

Original languageEnglish
Article numbere2307334120
JournalProceedings of the National Academy of Sciences - PNAS
Volume120
Issue number36
Early online date28 Aug 2023
DOIs
StatePublished - 5 Sep 2023

All Science Journal Classification (ASJC) codes

  • General

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