Weakly Anisotropic Superconductivity of Pr ₄ Ni ₃ O ₁₀ Single Crystals

Since the discovery of high-temperature superconductivity, studying the upper critical field and its anisotropy has been crucial for understanding the superconducting mechanism and guiding applications. Here, we perform <i>in situ</i> high-pressure angular-dependent electrical transport measurements on Pr₄Ni₃O₁₀ single crystals using a custom diamond anvil cell (DAC) rotator, confirming its anisotropic superconductivity. The anisotropy parameter γ, derived from the upper critical fields (μ₀<i>H</i>_c2) for H⊥<i>ab</i> and H//<i>ab</i>, is approximately 1.6, decreasing with increasing temperature and approaching 1 near <i>T</i>_c. Comparing effective mass anisotropy and interblock distance in cuprates and iron-based superconductors (FeSCs) reveals that Pr₄Ni₃O₁₀ single-crystal superconductors are consistent with a two-band model, where intralayer quantum confinement within the unit cell induces interlayer coherence, thereby leading to three-dimensional (3D) superconductivity. This study not only establishes the existence of weakly anisotropic superconductivity in bulk Ruddlesden-Popper nickelates but also provides critical insight into the role of dimensionality in high-temperature superconductivity.