Pressure induced superconductivity in the antiferromagnetic Dirac material BaMnBi2

Abstract

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, μ 0 H 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.

Ternary Bismuthide SrPtBi2: Computation and Experiment in Synergism to Explore Solid-State Materials

“…Using the predicted stoichiometry, we successfully synthesized the new SrPtBi 2 . Unlike other tetragonal 112-CuSmP 2 (BaMnBi 2 ) 19 or CuHfSi 2 (LaAuBi 2 ), 23 SrPtBi 2 adopts the orthorhombic structure with space group Pnma, which is analogous to YNiSn 2 . 24 Electronic structure calculations based on the experimental crystal information have confirmed the structural preference and chemical stability of orthorhombic SrPtBi 2 .…”

“…[16][17][18] The Zintl-Klemm concepts can be employed for interpreting the charge balance in BaMnBi 2 , which is an antiferromagnetic Dirac material coexisting with superconductivity at high pressure. 19 BaMnBi 2 can be formulated as Ba 2+ Mn 2+ Bi -Bi 3with Bi-Bi square planar in the structure. 20 However, if a system turns more complex with small difference in electronegativity among elements, chemical valence rules may fail in predicting crystal structures and properties.…”

“…For example, three-dimensional Dirac fermions have been detected in the topological Dirac semimetal Na 3 Bi. , Such materials can be used as transistors and other electronic devices . Usually, simple Bicontaining semiconductors or semimetals can be predicted using chemical valence arguments or Zintl–Klemm concepts. − Half-Heusler RPtBi (R = rare earth elements) compounds following 18e – rules show intriguing properties such as superconductivity in LuPtBi. − The Zintl–Klemm concepts can be employed for interpreting the charge balance in BaMnBi 2 , which is an antiferromagnetic Dirac material coexisting with superconductivity at high pressure . BaMnBi 2 can be formulated as Ba 2+ Mn 2+ Bi–Bi 3– with Bi–Bi square planar in the structure .…”

Spin quenching assisted by a strongly anisotropic compression behavior in MnP

“…Despite abundant of new efforts made by scientists after the discovery of the superconductivity in MnP, superconductivity in manganese-based materials is still very rare as of today. Besides MnP, only BaMnBi 2 was found to be superconducting under pressure [14] while MnAs and MnSb were predicted to be potential superconductors under pressure [15].…”

“Flat/steep band model” for superconductors containing Bi square nets

“…The calculations carried out early indicated that the Bi-6p and Mn-3d hybridization is significant. This compound has a superconducting transition at ~3.4 K under ~2.6 GPA [58], an effect of physical doping. An explanation for the superconductivity is not available, because the variations of the electronic structure under high pressure are not yet known.…”