Landau levels and Shubnikov-de Haas oscillations in monolayer transition metal dichalcogenide semiconductors

Kormányos, Andor and Rakyta, Péter and Burkard, Guido (2015) Landau levels and Shubnikov-de Haas oscillations in monolayer transition metal dichalcogenide semiconductors. NEW JOURNAL OF PHYSICS, 17. ISSN 1367-2630

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Abstract

We study the Landau level spectrum using a multi-band k · p theory in monolayer transition metal dichalcogenide semiconductors. We find that in a wide magnetic field range the Landau levels can be characterized by a harmonic oscillator spectrum and a linear-in-magnetic field term which describes the valley degeneracy breaking. The effect of the non-parabolicity of the band-dispersion on the Landau level spectrum is also discussed. Motivated by recent magnetotransport experiments, we use the self-consistent Born approximation and the Kubo formalism to calculate the Shubnikov de-Haas oscillations of the longitudinal conductivity. We investigate how the doping level, the spin-splitting of the bands and the broken valley degeneracy of the Landau levels affect the magnetoconductance oscillations. We consider monolayer MoS2 and WSe2 as concrete examples and compare the results of numerical calculations and an analytical formula which is valid in the semiclassical regime. Finally, we briefly analyze the recent experimental results (Reference [18]) using the theoretical approach we have developed.

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