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

Highlights: • The obtained λ is about 0.22 for KB₆, and T_C is only 0.14 K. • For K_1-xB₆, the λ and T_C can reach as high as 1.13 and 65.3 K, respectively. • K_1-xB₆ is potentially high-temperature superconducting. - Abstract: 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 T_C for KB₆ is only 0.22 and 0.14 K (${\mu }^{*}=0.1$), respectively. However, hole doping can greatly enhance the electron-phonon coupling strength for KB₆. For K_1-xB₆, the e-ph coupling strength λ and T_C can reach as high as 1.13 and 65.3 K, respectively. This indicates that K_1−xB₆ is potentially high-temperature superconducting.