Fig. 2: Maximizing the propagation asymmetry of HShPs in twisted bilayer α-MoO3.
From: Engineering shear polaritons in 2D twisted heterostructures
a TMM-calculated reflection coefficient for the bilayer. The reciprocal space map corresponds to d1 = 130 nm, d2 = 200 nm, and θ = 30°. White lines partition momentum space into four regions, originating from the global minimum momentum. The overlaid calculated red and blue curves are used as paths to calculate the line integral of Im(rpp) and obtain the shear factor, which quantifies the propagation asymmetry of HShPs. The resulting shear factor (blue to red colormap) as a function of θ: when both d1 and d2 vary equally (b); when only d1 varies while keeping d2 constant at 200 nm (c). Maximal asymmetry is found with different thicknesses over a narrow range of twist angles (red peak). The star indicates the shear factor calculated from IFCs in (a).
