Origins of bad-metal conductivity and the insulator–metal transition in the rare-earth nickelates
By R. Jaramillo, S. Ha, D. Silevitch, Shriram Ramanathan. Nature Physics, 2013
163 citations recorded by the source corpus.
Bad metals, such as the copper oxide superconductors, do conduct electricity but the origin of their poor conductivity is unclear. A study of disordered rare-earth nickelates now provides microscopic insights into bad-metal behaviour For most metals, increasing temperature (T) or disorder hastens electron scattering. The electronic conductivity (σ) decreases as T rises because electrons are more rapidly scattered by lattice vibrations. The value of σ decreases as disorder increases because electrons are more rapidly scattered by imperfections in the material. This is the scattering rate hypothesis, which has guided our understanding of metal conductivity for over a century. However, for so-called bad metals with very low σ this hypothesis predicts scattering rates so high as to conflict with Heisenberg’s uncertainty principle1,2. Bad-metal conductivity has remained a puzzle since its initial discovery in the 1980s in high-temperature superconductors. Here we introduce the rare-earth nickelates (RNiO3, R = rare-earth) as a class of bad metals. We study SmNiO3 thin films using infrared spectroscopy while varying T and disorder. We show that the interaction between lattice distortions and Ni–O covalence explains bad-metal conductivity and the insulator–metal transition. This interaction shifts spectral weight over the large energy scale established by the Ni–O orbital interaction, thus enabling very low σ without violating the uncertainty principle.
Subfields: Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Materials Chemistry
View Paper: https://www.semanticscholar.org/paper/2ffbe874a554b7700f843605032c006b4cb1068c
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
- S. Middey
- P. Mahadevan
- J. W. Freeland
- A. J. Millis
- D. Sarma
- J. Chakhalian
Citations in the corpus
- Physics of Ultrathin Films and Heterostructures of Rare-Earth Nickelates (2016, background): “Although resistance of these films surpasses the Mott-Ioffe-Regel limit at high temperature [89], unlike the case for the cuprates ρ eventually saturates for nickelates.”