Bulletin of the American Physical Society
APS March Meeting 2013
Volume 58, Number 1
Monday–Friday, March 18–22, 2013; Baltimore, Maryland
Session Y1: Invited Session: New Perspectives on Kondo Systems
8:00 AM–11:00 AM,
Friday, March 22, 2013
Room: Ballroom I
Sponsoring Unit: DCMP
Chair: David Goldhaber-Gordon, Stanford University
Abstract ID: BAPS.2013.MAR.Y1.2
Abstract: Y1.00002 : Visualizing heavy fermions emerging in a quantum critical Kondo lattice*
8:36 AM–9:12 AM
Preview Abstract Abstract
In solids containing elements with $f$ orbitals, the interaction between $f$-electron spins and those of itinerant electrons leads to the development of low-energy fermionic excitations with a heavy effective mass. These excitations are fundamental to the appearance of unconventional superconductivity and non-Fermi-liquid behavior observed in actinide- and lanthanide-based compounds. We use spectroscopic mapping with the scanning tunneling microscope to detect the emergence of heavy excitations with lowering of temperature in a prototypical family of cerium-based heavy-fermion compounds. We demonstrate the sensitivity of the tunneling process to the composite nature of these heavy quasiparticles, which arises from quantum entanglement of itinerant conduction and $f$ electrons. Scattering and interference of the composite quasiparticles is used to resolve their energy--momentum structure and to extract their mass enhancement, which develops with decreasing temperature. The lifetime of the emergent heavy quasiparticles reveals signatures of enhanced scattering and their spectral lineshape shows evidence of energy--temperature scaling. These findings demonstrate that proximity to a quantum critical point results in critical damping of the emergent heavy excitation of our Kondo lattice system.
*This work is funded by a DOE-BES grant. Partial support for instrumentation is provided by NSF-DMR, Keck Foundation, and NSF-MRSEC. PA also acknowledges support of a fellowship through the PCCM funded by NSF MERSEC.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2013.MAR.Y1.2
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