Electronic structure of the misfit layer compound : band structure calculations and photoelectron spectra

Abstract

IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document VersionPublisher's PDF, also known as Version of record Publication date: 1996Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Fang, C. M., Groot, R. A. D., Wiegers, G. A., & Haas, C. (1996). Electronic structure of the misfit layer compound (SnS)1.20TiS2: band structure calculations and photoelectron spectra. Journal of Physics%3A Condensed Matter, 8(11). DOI: 10.1088/0953-8984/8/11/011 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract. In order to understand the electronic structure of the incommensurate misfit layer compound (SnS) 1.20 TiS 2 we carried out an ab initio band structure calculation in the supercell approximation. The band structure is compared with that of the components 1T-TiS 2 and hypothetical SnS with a similar structure as in (SnS) 1.20 TiS 2 . The calculations show that the electronic structure is approximately a superposition of the electronic structures of the two components TiS 2 and SnS, with a small charge transfer from the SnS layer to the TiS 2 layer. The interlayer bonding between SnS and TiS 2 is dominated by covalent interactions. X-ray and ultraviolet photoelectron spectra of the valence bands are in good agreement with the band structure calculation.

Intercalation: Building a Natural Superlattice for Better Thermoelectric Performance in Layered Chalcogenides

“…In (SnS) 1.2 TiS 2 , the bands near the Fermi level show strong dispersion (about 1 eV) for directions with the k component perpendicular to c*, which is due to the strong covalent interlayer interaction. 19 In the direction parallel to c*, only a few bands (Ti 3d and Sn 5s) with dispersion of about 0.005 eV to 0.05 eV are observed. 19 However, because the micrograins in the bulk sample are not completely oriented, the electrical conducting behavior in the cross-plane direction may be intermixed with the in-plane one.…”

“…19 In the direction parallel to c*, only a few bands (Ti 3d and Sn 5s) with dispersion of about 0.005 eV to 0.05 eV are observed. 19 However, because the micrograins in the bulk sample are not completely oriented, the electrical conducting behavior in the cross-plane direction may be intermixed with the in-plane one. Both TiS 2 and (SnS) 1.2 (TiS 2 ) 2 show anisotropic power factors where the in-plane values are higher than the cross-plane ones (Fig.…”

“…Its crystal structure can be analyzed by analogy with the available data for the stage-1 compound (SnS) 1.2 TiS 2 , because the subsystems of SnS and TiS 2 are more or less identical in these two types of composition. 19,20 Both subsystems, SnS and TiS 2 , of (SnS) 1.2 (TiS 2 ) 2 are triclinic. The space groups are C-1 for SnS and F-1 for TiS 2 .…”

“…In (SnS) 1.2 (TiS 2 ) 2 , the rigid band model holds, and the band structure is a superposition of those of the SnS and TiS 2 subsystems, similar to the case of (SnS) 1.2 TiS 2 . 19,27,28 The bands near the Fermi level are mainly composed of Ti 3d, S 3p orbitals of the SnS and TiS 2 subsystems, and Sn 5s states. 19 Meanwhile, the position of the Fermi level in the 3d orbital of Ti atom can shift upward due to band-filling by electrons transferred from the SnS layer.…”

“…19,27,28 The bands near the Fermi level are mainly composed of Ti 3d, S 3p orbitals of the SnS and TiS 2 subsystems, and Sn 5s states. 19 Meanwhile, the position of the Fermi level in the 3d orbital of Ti atom can shift upward due to band-filling by electrons transferred from the SnS layer. Therefore, the Seebeck coefficient decreases as the density of states decreases.…”