Density of states and the problem of Sm valence

Surface alloying and mixed valence in thin layers of Ce and Pd on Ru(0001)

“…In the present study where the thin Ce-Pd layers on Ru have been annealed to elevated temperatures, the contributions to the Ce valence from the various parts of the layer would be difficult to determine. Finally, we note that an alternative description of valence in rare earths considers the itinerant nature of the shallow 4f orbitals [40]. The simple atomistic picture of 4f counts may possibly be in need for revision in descriptions of the electronic structure of such systems.…”

Dependence of STM Images οn Bias Polarity for Sm Layers οn Mo(110) and Mo(211) Surfaces

“…The calculated LDOS resembles only those peaks in photoemission spectra, which are believed to be pertinent to divalent Sm (that is, located about -2 eV with regard to E F ), while observed peaked structure about -5 eV has been attributed not to Sm 3+ , but to the influence of surface contaminations like O or H [16]. The hydrogenation of rare earth metals leads to a significant (22% for GdH 3 ) volume expansion [30][31][32][33].…”

“…In this regard, samarium metal presents a very interesting case due to a narrow f -derived peak in LDOS near below E F [16] [10,17]. The issue of Sm valence has been studied in a great number of papers devoted to investigations of the Sm thin films deposited on various metallic [18][19][20][21][22][23][24][25] and semiconductor substrates [26][27][28][29].…”

“…It should be mentioned that recent theoretical calculations [16] have shown that both [Xe] 4f 5 (5d6s) 3 and [Xe] 4f 6 (5d6s) 2 starting configurations of Sm, due to self-consistent redistribution of valence electrons, result in the same local density of states. The calculated LDOS resembles only those peaks in photoemission spectra, which are believed to be pertinent to divalent Sm (that is, located about -2 eV with regard to E F ), while observed peaked structure about -5 eV has been attributed not to Sm 3+ , but to the influence of surface contaminations like O or H [16].…”

Theoretical studies of Sm/Si(111)–n×1 (n=5, 7) and Sm/Si(111)–(8×2) structures

“…In particular, photoemission studies on the Sm silicide confirm that the valence of Sm changes from divalent at low coverage to a mixed valence (divalent and trivalent) in the (0.5-1.0) monolayer regime [14]. A complete review on the subject can be found in a recent paper by Yakovkin [15]. Experimental observations have revealed that a series of Sm-induced n  1 (n = 5, 7), n  2 (n = 3, 8) and a defective ð…”