Electronic structure, phonons, and high-temperature phonon-mediated superconductivity in lithium-intercalated diamond-like boron compounds

摘要

We present the first-principles calculations of lithium-intercalated diamond-like boron compounds LiB and LiB2. Although the pristine diamond structure of boron is dynamically unstable, LiB has no imaginary phonon mode after lithium intercalation. Our calculations show that LiB is an insulator with a direct energy gap of 1.45 eV. By removing a face-centered cubic sublattice of lithium from LiB, a metallic compound LiB(2)is obtained. Based on Wannier interpolation, the electron-phonon coupling in LiB(2)is accurately determined. We find that LiB(2)is stable above 12 GPa, with superconducting transition temperature close to 60 K.