Ambient-pressure high- Tc superconductivity in doped boron-nitrogen clathrates La(BN)5 and Y(BN)5

LaH10 exhibits the near-room-temperature superconductivity, but the high fabrication pressure exceeding 200 GPa limits the possibility of its experimental research and application. To examine the feasibility of high-temperature superconductivity at ambient pressure in light-element compounds, we study the crystal structure, metallization, and electron-phonon interaction of M(BN)5 (M = La and Y) with LaH10-like clathrate configuration, based on the first-principles calculations. The result shows that adopting B and N to substitute H, the strong sp3 hybridization between B and N greatly reduces the pressure to keep the dynamical stability. We predict that the strong electron-phonon coupling exists in M(BN)5 and the Tc values of La(BN)5 and Y(BN)5 reach 69 and 59 K at ambient pressure, respectively. As a result, the high-temperature superconductivity at ambient pressure in clathrate BN compounds has been proved theoretically, which provides a way to lower the work pressure of hydride superconductors.