Berlin 2008 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 14: Electronic Properties I

MM 14.1: Vortrag

Montag, 25. Februar 2008, 16:45–17:00, H 0111

Band structure mapping and calculations of metallic MoTe₂ — •Thorsten Zandt, Robert Heimburger, Christoph Janowitz, and Recardo Manzke — Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin

Calculations of the electronic structure have been performed using an self-consistent full potential linearized augmented-plane-wave (FP-LAPW) method in order to compare MoTe₂ in its two metallic forms, i. e. β- and Td-MoTe₂. In β- and Td-MoTe₂ the metal atom is displaced from the centre of an octahedron of Te atoms, and metal-metal chains with bond lengths only slightly longer than in the elemental metals occur along the layers. Thus one can guess that β- and Td-MoTe₂ are normal metals. From the band structure calculations we found that only few bands cross the Fermi energy. In the total DOS this leads to a distinct minimum at the Fermi energy. Therefore our interpretation is that MoTe₂ forms semimetals rather than metals, which is in good agreement with observed low conductivity [1]. The electronic structure between the monoclinic α-phase and orthorhombic β-phase of MoTe₂ is essentially unchanged. We discuss the theoretical results in comparison with experimental valence band studies using angle-resolved photoelectron spectroscopy taken from measurements at BESSY II.

[1] T. Zandt, H.Dwelk, C. Janowitz, and R. Manzke, Journal of Alloys and Compounds, 442, 216-218 (2007)