A chemical avenue to manipulate field-reentrant superconducting rivalries in infinite layer nickelates

Abstract: Recently, a preliminary magnetic field-reentrant superconductivity manifested in high critical-temperature (Tc) Eu-doped infinite-layer (IL) nickelates, beyond analogous discoveries exclusively in low-Tc systems. This arises more intriguing fundamental issues about potential quantum-phase boundary and criticality between unconventional superconductivity and field-reentrant-one, which are inexplicable owing to formidable challenges in growing IL-nickelates towards later-series rare-earths. Herein, we demonstrate the 4f-orbital related quantum rivalries between high-Tc and reentrant superconductivity in (Nd1-yRE'y)1-xEuxNiO2 (RE': Pr, Nd, Sm, Gd and Dy) system, via opening up the chemical avenue for a quantum leap in their growths. Robust magnetic field-reentrant superconductivity with uniaxial anisotropy is validated to fringe at boundary of the superconducting dome with optimal-Tc near 40 K. Reinforced reentry is realized via introducing Gd3+ with half-filled deeper 4f-orbital energy-states, compared to Eu2+, that strengthens on-site magnetic-moment. Our findings largely enrich the superconducting phase-diagram for nickelates, establishing an ideal platform for studying 4f-related unconventional superconductivity and quantum criticality.