Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 10: Elektronische Struktur II
O 10.3: Vortrag
Montag, 24. März 2003, 15:30–15:45, FOE/ORG
Divalent admixtures to the trivalent ground states in transition-metal compounds of Pr, Nd, Tb, and Dy — •Clemens Laubschat1, Michael Finken1, Serguei Molodtsov1, Yuri Kucherenko2, and Günther Behr3 — 1Institut für Oberflächenphysik und Mikrostrukturphysik, TU Dresden — 2Inst. of Metal Physics, National Academy of Science of Ukraine, UA-03142 Kiev, Ukraine — 3Leibniz Institute for Solid State and Materials Research Dresden
Large splittings of the 4f emission are observed in resonant photoemission (PE) spectra of Pr and Nd transition metal (TM) compounds that are much larger than expected multiplet effects and vary as a function of width and energy position of the TM-derived d bands. The phenomenon may quantitatively be described in the framework of the single-impurity Anderson model usually applied to Ce systems. However, while in the PE spectra of Ce systems splittings of the 4f emission are caused by the appearance of different 4fn final state configurations, the 4f derived emissions in Pr and Nd compounds reveal essentially 4fn−1 character. Hybridization leads to the formation of symmetric and antisymmetric linear combinations of f and d states that are responsible for the observed splittings of the PE signal. From the hybridization parameters derived, divalent admixtures to the trivalent ground states of up to 5% are concluded for Pr and Nd TM compounds. Similar but weaker effects are observed for Tb and Dy systems.