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arXiv · 2308.02313

The fate of quasiparticles at high-temperature

A. Hunter·S. Beck·E. Cappelli·F. Margot·M. Straub·Y. Alexanian·G. Gatti·M. D. Watson·T. K. Kim·C. Cacho·N. C. Plumb·M. Shi·M. Radović·D. A. Sokolov·A. P. Mackenzie·M. Zingl·J. Mravlje·A. Georges·F. Baumberger·A. Tamai
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Abstract

We study the temperature evolution of quasiparticles in the correlated metal Sr$_2$RuO$_4$. Our angle resolved photoemission data show that quasiparticles persist up to temperatures above 200~K, far beyond the Fermi liquid regime. Extracting the quasiparticle self-energy we demonstrate that the quasiparticle residue $Z$ increases with increasing temperature. Quasiparticles eventually disappear on approaching the bad metal state of Sr$_2$RuO$_4$ not by losing weight but via excessive broadening from super-Planckian scattering. We further show that the Fermi surface of Sr$_2$RuO$_4$ - defined as the loci where the spectral function peaks - deflates with increasing temperature. These findings are in semi-quantitative agreement with dynamical mean field theory calculations.

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A. Hunter, S. Beck, E. Cappelli, F. Margot, M. Straub, Y. Alexanian, G. Gatti, M. D. Watson, T. K. Kim, C. Cacho, N. C. Plumb, M. Shi, M. Radović, D. A. Sokolov, A. P. Mackenzie, M. Zingl, J. Mravlje, A. Georges, F. Baumberger, A. Tamai. 2023-08-04. The fate of quasiparticles at high-temperature. https://doi.org/10.1103/physrevlett.131.236502

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