Demonstrating Kondo behavior by temperature-dependent scanning tunneling spectroscopy

Elia Turco; Markus Aapro; Somesh C. Ganguli; Nils Krane; Robert Drost; Nahual Sobrino; Annika Bernhardt; Michal Juríček; Roman Fasel; Pascal Ruffieux; Peter Liljeroth; David Jacob

arXiv · 2310.09326

Demonstrating Kondo behavior by temperature-dependent scanning tunneling spectroscopy

Elia Turco·Markus Aapro·Somesh C. Ganguli·Nils Krane·Robert Drost·Nahual Sobrino·Annika Bernhardt·Michal Juríček·Roman Fasel·Pascal Ruffieux·Peter Liljeroth·David Jacob

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Abstract

The Kondo effect describes the scattering of conduction electrons by magnetic impurities, manifesting as an electronic resonance at the Fermi energy with a distinctive temperature evolution. In this letter, we present a critical evaluation of the current methodology employed to demonstrate Kondo behavior in transport measurements, underscoring the limitations of established theoretical frameworks and the influence of extrinsic broadening. We introduce a novel approach for analyzing spectroscopic indicators of the Kondo effect, employing the Hurwitz-Fano lineshape as a model for the Kondo resonance in the presence of extrinsic broadening. Through precise scanning tunneling spectroscopy measurements on an exemplary spin-1/2 Kondo system, phenalenyl on Au(111), we demonstrate the efficacy of our proposed protocol in extracting accurate intrinsic Kondo linewidths from finite-temperature measurements. The extracted linewidths exhibit a robust fit with a recently derived expression for the temperature-dependent intrinsic Kondo linewidth, providing compelling evidence for the validity of the underlying theory.

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Elia Turco, Markus Aapro, Somesh C. Ganguli, Nils Krane, Robert Drost, Nahual Sobrino, Annika Bernhardt, Michal Juríček, Roman Fasel, Pascal Ruffieux, Peter Liljeroth, David Jacob. 2023-10-13. Demonstrating Kondo behavior by temperature-dependent scanning tunneling spectroscopy. https://arxiv.org/abs/2310.09326

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