Absence of superconductivity and density-wave transition in ambient-pressure tetragonal La₄Ni₃O₁₀.

Abstract

The recent discovery of superconductivity in La₃Ni₂O₇ and La₄Ni₃O₁₀ under pressure stimulates intensive research interests. These nickelates crystallize in an orthogonal/monoclinic structure and have a density-wave transition at ambient pressure. The application of pressure triggers a transition to tetragonal structure (I4/mmm), which is believed to be a key prerequisite for the emergence of superconductivity. Here, we report the first tetragonal nickelates La₄Ni₃O₁₀ microcrystals at ambient pressure. In tetragonal La₄Ni₃O₁₀, transport measurements find that both density-wave and superconducting transitions are absent up to 160 GPa, indicating a robust tetragonal metallic ground state. Meanwhile, density functional theory calculations reveal a considerable contribution of d_z2 orbital to the Fermi surface. The concurrent absence of density-wave state and high-pressure superconductivity in tetragonal La₄Ni₃O₁₀ suggests that the density-wave state instead of tetragonal structure is crucial for the superconductivity in nickelates under pressure. Our findings impose important constraints on the mechanism of pressure-induced superconductivity in nickelates.