New Lutetium Oxide: Electrically Conducting Rock-Salt LuO Epitaxial Thin Film

Abstract

C-rare earth structure lutetium sesquioxide Lu 2 O 3 has been recognized as a high- k widegap insulator with closed shell Lu 3+ ions. In this study, rock-salt structure lutetium monoxide LuO with unusual valence of Lu 2+ (4f 14 5d 1 ), previously known as the gaseous phase, was synthesized as an epitaxial thin film by the pulsed laser deposition method. In contrast with transparent and highly insulating Lu 2 O 3 , LuO possessed a dark-brown color and high electrical conductivity concomitant with strong spin–orbit coupling as a manifestation of Lu 5d electron carriers.

First-principles study of the superconductivity in LaO

“…Figure1(a) shows the bulk crystal structure of lanthanum monoxide LaO. Similar to other reported rareearth monoxides[33][34][35]37 , LaO adopts a rock-salt structure with space group Fm-3m, which is composed of two face-centered cubic lattices, respectively, of La and O. The calculated lattice constants of bulk LaO are a = b = c = 5.164 Å, in good accordance with the previous experimental values (a = b = c = 5.144 Å)53 .…”

“…On the other hand, rare attention has been paid to the binary lanthanum compound LaO, probably due to its poor chemical stability in bulk form 32 . With the advance in the state-of-the-art oxide thin-film epitaxy techniques, several rare-earth monoxides with rock-salt structure including LaO have been successfully synthesized in the past five years [33][34][35][36][37] . Particularly, the LaO thin films with a thickness of approximately 20 nm deposited on different substrates show bulk superconductivity with a T c around 5 K 36 .…”

Band Gap Modeling of Different Ternary and Quaternary Alumina Garnet Phases Y3(AlxGa1–x)5O12 (YAGG) and Lu3(AlxGa1–x)5O12 (LuAGG). A Semiempirical Approach

“…The E exc value is in good agreement with the value of the exciton energy peak reported by different authors, ,,, while the derived E fa value is in very good agreement with the values of direct optical band gap reported in the literature for cubic-Y 2 O 3 ( E g.opt = 5.73–5.825 eV). , Analogously for c-Lu 2 O 3 a value of E exc (RT) = 5.92 eV is derived from eq from which value an E g.opt value of 5.67 eV is obtained at room temperature. The value of E exc (RT) is in good agreement, too, with the value of exciton energy peak experimentally measured, at 300 K, for a single crystal of c-Lu 2 O 3 , while the E g.opt value is in good agreement with the values of E g,opt = 5.50–5.80 eV reported in Table S2 for crystalline c-Lu 2 O 3 films. ,, g,h…”

A high-TC heavy rare earth monoxide semiconductor TbO with a more than half-filled 4f orbital

“…The Tb 2 O 3 phase was probably caused by surface oxidation as reported in corresponding sesquioxides of YO, LuO, and GdO thin films. 3,5,9 The strong XRD peak intensity of Tb 2 O 3 was attributed to a nearly 10-fold larger structure factor for Tb 2 O 3 , from which the volume fraction of the TbO phase in the film was estimated to be 83%. The absence of the Tb metal phase was consistent with XPS measurements (Fig.…”

“…1 The rare earth monoxide EuO (Eu 2+ : [Xe] 4f 7 ) is an archetypal ferromagnetic semiconductor with a large volume magnetization owing to a half-filled 4f 7 orbital of the Eu 2+ ion (7μ B per Eu ion), in spite of its low Curie temperature (T C ) of 69 K. 2 Recently, various rare earth monoxides with divalent rare earth ions have been synthesized via thin film epitaxy. [3][4][5][6][7][8][9][10][11] Among them, GdO (Gd 2+ : [Xe] 4f 7 5d 1 ) was reported to be a high T C ferromagnetic semiconductor with T C of 276 K. 9 Both EuO and GdO possess a half-filled 4f 7 orbital with only spin angular momentum, i.e. zero orbital angular momentum.…”