Signature of quantum criticality in photoemission spectroscopy at elevated temperature

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dc.creatorKlein, M.
dc.creatorNuber, A.
dc.creatorReinert, F.
dc.creatorKroha, J.
dc.creatorStockert, O.
dc.creatorLöhneysen, H. v.
dc.date2008-06-19
dc.date2008-12-09
dc.date.accessioned2026-07-07T12:22:23Z
dc.date.available2026-07-07T12:22:23Z
dc.descriptionA quantum phase transition (QPT) in a heavy-fermion (HF) compound may destroy the Fermi liquid groundstate. However, the conditions for this breakdown have remained obscure. We report the first direct investigation of heavy quasiparticle formation and breakdown in the canonical system CeCu$_{6-x}$Au$_x$ by ultraviolet photoemission spectroscopy at elevated temperatures without the complications of lattice coherence. Surprisingly, the single-ion Kondo energy scale $T_K$ exhibits an abrupt step near the quantum critical Au concentration of $x_c=0.1$. We show theoretically that this step is expected from a highly non-linear renormalization of the local spin coupling at each Ce site, induced by spin fluctuations on neighboring sites. It provides a general high-temperature indicator for HF quasiparticle breakdown at a QPT.
dc.descriptionPublished version, PRL, minor changes in wording
dc.identifierhttps://arxiv.org/abs/0806.3296
dc.identifierhttp://arxiv.org/abs/0806.3296
dc.identifierPhys. Rev. Lett 101, 266404 (2008)
dc.identifierdoi:10.1103/PhysRevLett.101.266404
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/213634
dc.subjectStrongly Correlated Electrons
dc.titleSignature of quantum criticality in photoemission spectroscopy at elevated temperature
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