Robust antiferromagnetism preventing superconductivity in pressurized (Ba 0.61 K 0.39)Mn2Bi2

Pressure induced superconductivity in the antiferromagnetic Dirac material BaMnBi2

The so-called Dirac materials such as graphene and topological insulators are a new class of matter different from conventional metals and (doped) semiconductors. Superconductivity induced by doing or applying pressure in these systems may be unconventional, or host mysterious Majorana fermions. Here, we report a successfully observation of pressure-induced superconductivity in an antiferromagnetic Dirac material BaMnBi₂ with T_c of ~4 K at 2.6 GPa. Both the higher upper critical field, μ₀H_c2(0) ~ 7 Tesla, and the measured current independent of T_c precludes that superconductivity is ascribed to the Bi impurity. The similarity in ρ_ab(B) linear behavior at high magnetic fields measured at 2 K both at ambient pressure (non-superconductivity) and 2.6 GPa (superconductivity, but at the normal state), as well as the smooth and similar change of resistivity with pressure measured at 7 K and 300 K in zero field, suggests that there may be no structure transition occurred below 2.6 GPa, and superconductivity observed here may emerge in the same phase with Dirac fermions. Our findings imply that BaMnBi₂ may provide another platform for studying SC mechanism in the system with Dirac fermions.