Chemistry of Materials · 2020 · 13 citations · 31 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsMaterials PhysicsSolid State PhysicsCluster CompoundsCrystal ChemistryCrystallographyInorganic MaterialsStrongly Correlated Electron SystemsSuperconducting MaterialsCluster Electron CountingCritical TemperatureCrystal Structure-property RelationshipsElectron Counting RulesElectron-phonon ScatteringPhase Transition TemperatureSuperconducting Critical Temperature
Endohedral cluster superconductors are an emerging field, where simple electron counting rules govern the phase stability and transition temperature. Nontrivial microscopic properties of the superconducting state, including strong electron–phonon coupling and multigap superconductivity, raise fundamental interest in studying these materials. Herein, Mo4Ga20.38(1)S0.62(1), Mo4Ga20Se, Mo4Ga20Te, and Mo4Ga20Sb endohedral cluster compounds were synthesized in the form of bulk polycrystalline samples and single crystals. Together with the recently reported Mo4Ga21–x–δSnx, these compounds belong to the new Mo4Ga21 structure type with notable functionality: all the discovered representatives show superconducting properties. The observed critical temperatures of 5.1, 3.3, 4.6, and 6.6 K for the S-, Se-, Te-, and Sb-containing compounds, respectively, correlate well with the experimental values of the Sommerfeld coefficient. An emerging role of the electron–phonon coupling may be responsible for the enhancement of critical temperature in the case of Mo4Ga20Sb.
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