Regulation of near-field radiative heat transfer between two-dimensional borophene sheets under uniaxial strain based on first-principles calculations

This study investigates the near field radiative heat transfer (NFRHT) regulation behavior of χ 3 -phase two-dimensional borophene (Bχ 3 ) sheets under uniaxial strain, based on first-principles calculations and fluctuation-dissipation theory. By analyzing the dielectric functions and spectral heat transfer coefficients of borophene under different strain conditions, the near-field radiative heat transfer properties of single-layer and bilayer borophene under x / y -axis strain are explored, where the x -direction corresponds to the Bχ 3 lattice direction a , and the y -axis is perpendicular to the x -axis. Results indicate that strain significantly alters the optical properties of borophene. Under x -axis strain, the normalized heat transfer coefficient first decreases then increases with strain, reaching a maximum increase of 3.6 times compared to the unstrained state. In contrast, y -axis strain exhibits a monotonic increase, with a maximum enhancement of approximately 126 times. Furthermore, bilayer borophene exhibited more pronounced near-field radiative heat transfer modulation effects than monolayer borophene, particularly under tensile strain. The study demonstrates that carefully designing the direction and magnitude of strain enables precise control over near-field heat transport, providing a theoretical basis for developing efficient thermal management devices based on borophene.