Strain dependence of photoluminescence and circular dichroism in transition metal dichalcogenides: a k.p analysis

Abstract

Within a two-band $k\cdot p$ method we analyze different types of strain for the $K$ valley optical characteristics of a freestanding monolayer MoS${}_2$, MoSe${}_2$, WS${}_2$ and WSe${}_2$. We predict that circular polarization selectivity for energies above the direct transition onset deteriorates/improves by tensile/compressive strain. Wide range of available strained-sample photoluminescence data can be reasonably reproduced by this simple bandstructure combined with accounting for excitons at a variational level. According to this model strain impacts optoelectronic properties through its hydrostatic component, whereas the shear strain only causes a rigid wavevector shift of the valley. Furthermore, under the stress loading of flexible substrates the presence of Poisson's effect or the lack of it are examined individually for the reported measurements.

arXiv commentRevised, 10 pages, 3 figures; published version

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• Localized Excitons in NbSe${}_2$-MoSe${}_2$ Heterostructures
• Fundamental relations for anomalous thermoelectric transport coefficients in the non-linear regime
• Strain-dependent exciton diffusion in transition metal dichalcogenides
• Second-harmonic generation enhancement in monolayer transition-metal dichalcogenides by an epsilon-near-zero substrate
• Strain control of exciton and trion spin-valley dynamics in monolayer transition metal dichalcogenides
• A colloquium on the variational method applied to excitons in 2D materials
• Local tuning of WS2 photoluminescence using polymeric micro-actuators in a monolithic van der Waals heterostructure
• Probing the uniaxial strain-dependent valley drift and Berry curvature in monolayer MoSi${}_2$N${}_4$
• Engineering robust strain transmission in van der Waals heterostructure devices
• Criteria for deterministic single-photon emission in two-dimensional atomic crystals
• Geometric band properties in strained monolayer transition metal dichalcogenides using simple band structures
• Biaxial strain tuning of exciton energy and polarization in monolayer WS2