Robust antiferromagnetism preventing superconductivity in pressurized (Ba(0.61)K(0.39))Mn(2)Bi(2)

BaMn(2)Bi(2) possesses an iso-structure of iron pnictide superconductors and similar antiferromagnetic (AFM) ground state to that of cuprates, therefore, it receives much more attention on its properties and is expected to be the parent compound of a new family of superconductors. When doped with potassium (K), BaMn(2)Bi(2) undergoes a transition from an AFM insulator to an AFM metal. Consequently, it is of great interest to suppress the AFM order in the K-doped BaMn(2)Bi(2) with the aim of exploring the potential superconductivity. Here, we report that external pressure up to 35.6 GPa cannot suppress the AFM order in the K-doped BaMn(2)Bi(2) to develop superconductivity in the temperature range of 300 K–1.5 K, but induces a tetragonal (T) to an orthorhombic (OR) phase transition at ~20 GPa. Theoretical calculations for the T and OR phases, on basis of our high-pressure XRD data, indicate that the AFM order is robust in the pressurized Ba(0.61)K(0.39)Mn(2)Bi(2). Both of our experimental and theoretical results suggest that the robust AFM order essentially prevents the emergence of superconductivity.