TY  - JOUR
AU  - Mittal, R.
AU  - Pintschovius, L.
AU  - Lamago, D.
AU  - Heid, R.
AU  - Bohnen, K-P
AU  - Reznik, D.
AU  - Chaplot, S. L.
AU  - Su, Y.
AU  - Kumar, N.
AU  - Dhar, S. K.
AU  - Thamizhavel, A.
AU  - Brückel, Thomas
TI  - Anomalous phonons in CaFe 2 As 2 explored by inelastic neutron scattering3
JO  - Journal of physics / Conference Series
VL  - 251
SN  - 1742-6596
CY  - Bristol
PB  - IOP Publ.
M1  - FZJ-2017-06677
SP  - 012008 -
PY  - 2010
AB  - Extensive inelastic neutron scattering measurements of phonons on a single crystal of CaFe2As2 allowed us to establish a fairly complete picture of phonon dispersions in the main symmetry directions. The phonon spectra were also calculated by density functional theory (DFT) in the local density approximation (LDA). There are serious discrepancies between calculations done for the optimized structure and experiment, because the optimised structure is not the ambient pressure structure but is very close to the "collapsed" structure reached at p = 3.5 kbar. However, if the experimental crystal structure is used the calculation gives correct frequencies of most phonons. The most important new result is that linewidths/frequencies of certain modes are larger/softer than predicted by DFT-LDA. We also observed strong temperature dependence of some phonons near the structural phase transition near 172 K. This behavior may indicate anomalously strong electron phonon coupling and/or anharmonicity, which may be important to the mechanism of superconductivity.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000291982100008
DO  - DOI:10.1088/1742-6596/251/1/012008
UR  - https://juser.fz-juelich.de/record/837907
ER  -