Extending the metal to insulator transitions of rare‐earth nickelates towards low temperature ranges

Abstract

AbstractAlthough the d‐band correlated rare‐earth nickelates (ReNiO3) exhibit broadly adjustable metal to insulator transitions (MIT) that enables emerging correlated electronic applications, it is yet difficult to regulate their associated critical temperature (TMIT) below 100 K. Herein, we extend the lower limit in TMIT of ReNiO3 down to 83 K while maintaining an abrupt switch in resistivity via partial La‐substitution of PrNiO3. The near edge X‐ray fine structure analysis and density function theory calculations indicate the strengthening in the metallic orbital configuration and reduction in the ground state band gap via La‐substitution of Re in NdNiO3 and PrNiO3. In contrast, analogous Ce substitution cannot reduce the TMIT of ReNiO3 owing to its valance variability toward +4, while La partial substitution of ReNiO3 with middle or heavy rare‐earth (e.g., Sm) easily disturb the co‐occupation of the Re‐site by the two rare‐earths as one dispersive phase.