Potentially high-temperature superconductivity in K1−xB6: A first-principles prediction

Electronic structure, lattice dynamics, and superconducting properties for KB6 are obtained by first-principles calculations. We show that the stoichiometric KB6 have a weak electron-phonon interaction. The obtained electron-phonon coupling strength λ and the superconducting transition temperature TC for KB6 is only 0.22 and 0.14 K (μ*=0.1), respectively. However, hole doping can greatly enhance the electron-phonon coupling strength for KB6. For K1-xB6, the e-ph coupling strength λ and TC can reach as high as 1.13 and 65.3 K, respectively. This indicates that K1−xB6 is potentially high-temperature superconducting.