Electronic structure of Ln2O2Te (Ln=La, Sm and Gd) by X-ray absorption spectroscopy. (December 2018)

• Record Type: Journal Article
• Authors: Gautam, Sanjeev; Chae, Keun Hwa; Llanos, Jaime; Peña, Octavio; Asokan, K.
• Is Part Of: Vacuum. Volume 158(2018)
• Page Start: 39
• Page End: 41
• Publication Date: 2018-12
• Subjects: Rare earth alloys and compounds -- NEXAFS -- Oxychalcogenide -- Thermoelectric material; 71.20.Ps -- 78.70.Dm -- 84.60.Rb; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2018.09.008
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: The oxytellurides are layered structure material which shows low lattice thermal conductivity and hence making them suitable for high temperature thermoelectric applications. We report the electronic structural properties of rare-earth doped oxytellurides [Ln2 O2 Te (Ln = La, Sm and Gd)] prepared by solid state reaction method. This research is focused on the suitability of rare-earth oxychalcogenide as a thermoelectric material using the electronic structure investigations. The X-ray absorption spectra at O K-edge show the O 2 p bonding with Ln 5 d and 4 f and Te 5s states and the Ln M-edges show that the valences of Ln are to be trivalent or mixed states. The Ln M-edges are also simulated with Cowan code, and electronic structures of these oxytellurides are discussed. The substitution of different rare earth metals at the Ln-site, may enhance the thermoelectric property and stability of the material. Graphical abstract: Highlights: Oxytellurides Ln2 O2 Te (Ln = La, Sm and Gd) synthesized by the solid state reaction. NEXAFS shows the O 2 p bonding with Ln 5d and, 4f and Te 5s states. Ln M-edge NEXAFS confirm the valences of Ln are to be trivalent and mixed. Cowan code and Thole et al. hypothesis are used to discuss the electronic structure.