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Band structure of MoS_2, MoSe_2, and alpha-MoTe_2: Angle-resolved photoelectron spectroscopy and ab-initio calculations

Th. Boeker·R. Severin·A. Mueller·C. Janowitz·R. Manzke·D. Voss·P. Krueger·A. Mazur·J. Pollmann
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Abstract

In this work the complete valence-band structure of the molybdenum dichalcogenides MoS_2, MoSe_2, and alpha-MoTe_2 is presented and discussed in comparison. The valence bands have been studied using both angle-resolved photoelectron spectroscopy (ARPES) with synchrotron radiation, as well as, ab-initio band-structure calculations. The ARPES measurements have been carried out in the constant-final-state (CFS) mode. The results of the calculations show in general very good agreement with the experimentally determined valence-band structures allowing for a clear identification of the observed features. The dispersion of the valence bands as a function of the perpendicular component k_perp of the wave vector reveals a decreasing three-dimensional character from MoS_2 to alpha-MoTe_2 which is attributed to an increasing interlayer distance in the three compounds. The effect of this k_perp dispersion on the determination of the exact dispersion of the individual states as a function of k_parallel is discussed. By performing ARPES in the CFS mode the k_parallel-component for off-normal emission spectra can be determined. The corresponding k_perp-value is obtained from the symmetry of the spectra along the GammaA, KH, and ML line, respectively.

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Th. Boeker, R. Severin, A. Mueller, C. Janowitz, R. Manzke, D. Voss, P. Krueger, A. Mazur, J. Pollmann. 2001-07-26. Band structure of MoS_2, MoSe_2, and alpha-MoTe_2: Angle-resolved photoelectron spectroscopy and ab-initio calculations. https://doi.org/10.1103/physrevb.64.235305

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