2022/02/07 by Chen, Xinglong, Zheng, Hong, Phelan, Daniel +6
#FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2202.03479
Low-valent nickelates Rn+1NinO2n+2 (R = rare earth) containing Ni1+ (d9) with a quasi-two-dimensional (quasi-2D) square planar coordination geometry possess structural and electronic properties that are similar to those of high-Tc cuprates, including superconductivity itself in the doped infinite layer (n = ∞) RNiO2 system. Within this Rn+1NinO2n+2 nickelate family, the crystallographic isomorphs Pr4Ni3O8 and La4Ni3O8 exhibit singularly different ground states: Pr4Ni3O8 is metallic and La4Ni3O8 is a charge- and spin-stripe ordered insulator. To explore and understand the ground state evolution from metallic Pr4Ni3O8 to stripe-ordered La4Ni3O8 in the R4Ni3O8 family, we have grown a series of isovalent-substituted single crystals (Pr1-xLax)4Ni3O8. Combining thermodynamic, transport, magnetic, and synchrotron X-ray single crystal diffraction measurements, we reveal a transition between metallic and stripe-insulator phase regions, with a putative quantum phase transition at x = 0.4. We propose two possible models for (Pr1-xLax)4Ni3O8: an electronically inhomogeneous system that could serve as a candidate for exploring quantum Griffiths phase physics and a homogeneous system with a putative quantum critical point at the phase boundary.