1. Evolution of the Kondo lattice and non-Fermi liquid excitations in a heavy-fermion metal
- Author
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Stefanie Hartmann, Sven Friedemann, Cornelius Krellner, Steffen Wirth, C. Geibel, Frank Steglich, Lin Jiao, Qimiao Si, Silvia Seiro, and Stefan Kirchner
- Subjects
Science ,Scanning tunneling spectroscopy ,FOS: Physical sciences ,General Physics and Astronomy ,02 engineering and technology ,Electron ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Condensed Matter - Strongly Correlated Electrons ,Lattice (order) ,Quantum critical point ,0103 physical sciences ,ddc:530 ,lcsh:Science ,010306 general physics ,Quantum ,Physics ,Multidisciplinary ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed matter physics ,General Chemistry ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Magnetic field ,Quasiparticle ,lcsh:Q ,Condensed Matter::Strongly Correlated Electrons ,Fermi liquid theory ,0210 nano-technology - Abstract
Strong electron correlations can give rise to extraordinary properties of metals with renormalized quasiparticles which are at the basis of Landau's Fermi liquid theory. Near a quantum critical point, these quasiparticles can be destroyed and non-Fermi liquid behavior ensues. YbRh$_2$Si$_2$ is a prototypical correlated metal as it exhibits quasiparticles formation, formation of Kondo lattice coherence and quasiparticle destruction at a field-induced quantum critical point. Here we show how, upon lowering the temperature, the Kondo lattice coherence develops and finally gives way to non-Fermi liquid electronic excitations. By measuring the single-particle excitations through scanning tunneling spectroscopy down to 0.3 K, we find the Kondo lattice peak emerging below the Kondo temperature $T_{\rm K} \sim$ 25 K, yet this peak displays a non-trivial temperature dependence with a strong increase around 3.3 K. At the lowest temperature and as a function of an external magnetic field, the width of this peak is minimized in the quantum critical regime. Our results provide a striking demonstration of the non-Fermi liquid electronic excitations in quantum critical metals, thereby elucidating the strange-metal phenomena that have been ubiquitously observed in strongly correlated electron materials., 7 pages, 5 figures
- Published
- 2018