Mechanically Tunable Near-Field Radiative Heat Transfer between Monolayer Black Phosphorus Sheets

As a cutting-edge two-dimensional (2D) material, black phosphorous (BP) has been demonstrating a promising performance in the field of near-field radiative heat transfer (NFRHT) due to the excitation ability of its surface plasmon polaritons. Here, we have systematically demonstrated the effect of mechanical strain on the NFRHT between two separate BP sheets. First-principles calculations predict that a certain amount of mechanical strain (4% along biaxial or 6% along zigzag (ZZ)) can trigger an orthogonal switch of anisotropic optical conductivity by regulating the effective mass of electrons. The mismatched coupling of surface plasmon polaritons between the pristine and strained BP results in a 73% change in NFRHT. The studied mechanically tunable NFRHT unfolds a new degree of freedom for controlling the near-field heat transfer and sheds light on an invaluable approach to designing two-dimensional material-based thermal and electrical applications.