The emergence of superconductivity in BaNi2(Ge1-xPx)2 at a structural instability

Abstract

The physical properties and structural evolution of the 122-type solid solution BaNi2(Ge1-xPx)2 are reported. The in-plane X-X (X = Ge1-xPx) dimer formation present in the end member BaNi2Ge2, which results in a structural transition to orthorhombic symmetry, is completely suppressed to zero temperature on P substitution near x = 0.7, and a dome-shape superconducting phase with a maximum Tc = 2.9 K emerges. Clear indications of phonon softening and enhanced electron-phonon coupling are observed at the composition of the structural instability. Our findings show that dimer breaking offers new possibilities as a tuning parameter of superconductivity.

14 pages, 4 figures

References in corpus (4)

• Superconductivity Induced by Bond Breaking in the Triangular Lattice of IrTe2
• Nickel-based phosphide superconductor with infinite-layer structure, BaNi2P2
• Giant Phonon Softening and Enhancement of Superconductivity by Phosphorus Doping of BaNi2As2
• Fermi surface in BaNi${}_2$P${}_2$

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