Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 43: Correlated Electrons: f-Electron & Heavy Fermion Systems

TT 43.2: Vortrag

Mittwoch, 9. März 2016, 09:45–10:00, H20

Combined crystal field - phonon excitations in non-centrosymmetric heavy fermion CeAuAl₃ — •Petr Čermák¹, Astrid Schneidewind¹, Christian Franz^2,3, Rudolf Schönmann², Oleg Sobolev^3,4, and Christian Pfleiderer² — ¹Jülich Centre for Neutron Science, MLZ, Garching, DE — ²Physik-Department, Technische Universität München, Garching, DE — ³FRM II, Technische Universität München, Garching, DE — ⁴Institute for Physical Chemistry, Georg-August-University, Göttingen, DE

Hybridized excitations that comprise of well-understood collective modes have received increasing interest as the possible origin of unconventional materials properties. In strongly correlated systems the effects of electron-phonon interactions are typically neglected, being deemed not important for the overall understanding. Recently, neutron experiment on CeCuAl₃ has provided putative evidence for a combined crystal field - phonon excitation [1]. In turn, an important question concerns to what extent these modes are a generic property, say, at least of the entire series of CeTAl₃ compounds (T: transition metal element) or even f-electron systems in a more general sense.

Our triple axis neutron measurement on single-crystal CeAuAl₃ revealed a new weakly dispersive excitation in contrast with earlier reports on polycrystals [2], suggesting rather generic phenomena. We have further proven, that this excitation is magnetically driven and is strongly connected with localized optical acoustic modes.
D.T. Adroja et al., Phys. Rev. Lett. 108, 216402 (2012)
D.T. Adroja et al., Phys. Rev. B 91, 134425 (2015)