Frequency switchable correlated transports in perovskite rare-earth nickelates

Abstract

While electron correlations were previously recognized to result in direct current (DC) transportation properties beyond-conventional (e.g., metal-to-insulator transitions, bad metal, thermistors), their respective influences on the alternating current (AC) transport are largely overlooked. Herein, active regulation of the electronic functionalities of d-band correlated rare-earth nickelate (ReNiO₃) thin films, by simply utilizing their electronic responses to AC-frequencies (f_AC) is demonstrated. Assisted by temperature dependent near edge X-ray absorption fine structure analysis, positive temperature dependences in the Coulomb viscosity of ReNiO₃ were discovered, which moderate their AC impedance (R′ + iR′′). Distinguished crosslinking among R′–f_AC measured in nearby temperatures is observed that differs to conventional oxides. This enables active adjustability in correlated transports of ReNiO₃, among NTCR-, T_Delta- and PTCR-thermistors, via f_AC from the electronic perspective without varying materials or device structures. Furthermore the T_Delta–f_AC relationship can be widely adjusted via the Re composition and interfacial strains. The AC-frequency sensitivity discovered in ReNiO₃ leads the way to a new freedom in regulating and switching the device working states beyond the present semiconductor technologies. It opens up a new model for enriching novel electronic applications in automatic transmission, artificial intelligence in sensing temperatures or thermal perturbations.