Phonons in a highly-correlated electron system: the heavy-fermion superconductor CeCu2Si2
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Date
2014-02-04
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Institute of Physics
Abstract
CeCu2Si2 crystallizes in the tetragonal ThCr2Si2-type structure with 5 atoms in the primitive
unit cell. It exhibits non-conventional superconductivity driven by low-energy magnetic
excitations [1]. The Ce3+ Hund’s rule J=5/2 ground state is split by the action of the crystalline
electric field into 3 doublets, with two excited doublets forming a quasi-quartet at around 30
meV [2]. Except for Raman data [3] no information about the lattice dynamics was available
up to date. We therefore performed inelastic neutron scattering at low temperatures (3 K and
10 K) on a large single crystal on the thermal triple-axis spectrometers PUMA (FRM II) and
TAIPAN (OPAL) to determine the phonon dispersion relations in the [001/110] plane. The
measured dispersion curves will be compared with ab-initio DFT calculations. In addition we
could refine the crystal field level scheme resulting in the observation that the excited quasiquartet
actually consists of two considerably broadened doublets situated at around 28 meV
and 35 meV, respectively.
Description
Keywords
Phonons, Electrons, Fermions, Cerium, Copper, Silicon, Superconductors, Excitation, Crystal lattices, OPAL Reactor, MeV range 10-100
Citation
Loewenhaupt, L., Danilkin, S., Capogna,L., Schneidewind, A., Stockert, O., & Hradil, K. (2014). Phonons in a highly-correlated electron system: the heavy-fermion superconductor CeCu2Si2. Paper presented at the 38th Annual Condensed Matter and Materials Meeting 2014, Waiheke Island Resort, Waiheke, Auckland, New Zealand 4th February - 7th February, 2014. Retrieved from: https://physics.org.au/wp-content/uploads/cmm/2014/Wagga2014proceedings.pdf