Rope coiling

Amnuanpol, Sitichoke

doi:10.1007/s12043-017-1470-4

Cited by 2 publications

(1 citation statement)

References 21 publications

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“…As shown in table B1, k are crystal-direction-independent, whereas q is crystaldirection-dependent for both materials. The changes in the bond length and angle between the chalcogen atoms via the normal strain are known to be larger in the zigzag direction than in the armchair direction [54]. In this regard, we found that the application of ε e xx in the zigzag direction, compared to the armchair direction, induces a K-Q crossover transition with small ε 0 , where ε 0 is the normal strain at which the K-and Q-valley minima cross.…”

Section: Appendix B Normal-strain-induced Band Anti-crossing and Spin...mentioning

confidence: 67%

Shear-strain-mediated photoluminescence manipulation in two-dimensional transition metal dichalcogenides

Hwang¹,

Lee²,

Kim³

et al. 2021

2D Mater.

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In two-dimensional transition metal dichalcogenides, normal strain can modulate electronic band structures, yet leaving the optical selection rules intact. In contrast, a shear strain can perturb the spin-valley locked band structures and possibly induce mixing of the spin subbands which in turn can transfer oscillator strength between spin-allowed bright and spin-forbidden dark excitons. Here, we report a novel scheme to manipulate photoluminescence (PL) in a monolayer WSe2-MoSe2 lateral heterostructures, controlled by an external bending method in which strong out-of-plane shear strain (OSS) of up to 5.6% accompanies weak in-plane normal strain up to 0.72%. The spectra revealed a striking dependence on the bending direction that is stagnant in the negative (compressive) strain region and then rapidly changes with increasing positive (tensile) strain. The dependency of the PL signal under tensile bending was represented not only by the large energy shift ( > 40 meV) of the lowest excited states of both the WSe2 and MoSe2 monolayers, but also by the tendency to violate the optical selection rules that brightens (darkens) the excitons of the WSe2 (MoSe2) side. The analyses on the observed energy shifts and PL intensity changes confirm the different origins in compressive bending compared with tensile bending. The well-established band-anticrossing is identified to be affecting only the compressive deformation region. The spectral changes in the tensile region, on the other hand, originates mainly from the generation of an off-diagonal perturbation to a spin-specific Hamiltonian induced by OSS. The degree of spin-state mixing, which correlates precisely with the spin-flip coefficient of the theoretical model, is further represented by the OSS matrix elements, the spin splitting energy, and the shear deformation potential.

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Section: Appendix B Normal-strain-induced Band Anti-crossing and Spin...mentioning

confidence: 67%