title: Type-I superconductivity in KBi₂ single crystals.
abstract: We report on the detailed transport, magnetic, thermodynamic properties and theoretical calculation of KBi2 single crystals in superconducting and normal states. KBi2 exhibits metallic behavior at a normal state and enters the superconducting state below T(c) = 3.573 K. Moreover, KBi2 exhibits low critical fields in all measurements, field-induced crossover from second- to first-order phase transition in specific heat measurements, the typical magnetization isotherms of type-I superconductors, and a small Ginzburg-Landau parameter κ(GL) = 0.611. These results clearly indicate that KBi2 is a type-I superconductor with a thermodynamic critical field H(c) = 234.3(3) Oe.
authors.affiliation: Department of Physics, Renmin University of China, Beijing 100872, People's Republic of China. Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing 100872, People's Republic of China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Sun
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Hechang
authors.initials: H
authors.lastname: Lei