Perfect electromagnetic wave absorption in black phosphorus: A multi-scale approach

Using the density functional theory of electronic structure, we compute the anisotropic dielectric response of bulk black phosphorus subject to strain. Employing the obtained permittivity tensor, we solve Maxwell’s equations and study the electromagnetic response of a layered structure comprising a film of black phosphorus stacked on a metallic substrate. Our results reveal that a small compressive or tensile strain,~4%, exerted either perpendicular or in the plane to the black phosphorus growth direction, efficiently controls the epsilon-near-zero response, and allows a perfect absorption tuning from low-angle of the incident beam to high values while switching the energy flow direction. Incorporating spatially inhomogeneous strain models, we also find that for certain thicknesses of the black phosphorus, near-perfect absorption can be achieved through controlled variations of the in-plane strain [1].

[1] M. Alidoust, K. Halterman, D. Pan, M. Willatzen, J. Akola, Phys. Rev. B 102, 115307 (2020)