Disappearance of the metal-insulator transition in iridate pyrochlores on approaching the ideal R2Ir2O7 stoichiometry
| Autor: | Arthur W. Sleight, Arthur P. Ramirez |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Condensed matter physics Mott insulator Pyrochlore 02 engineering and technology General Chemistry engineering.material 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Semimetal Oxidation state Electrical resistivity and conductivity 0103 physical sciences Materials Chemistry engineering Crystallite Metal–insulator transition 010306 general physics 0210 nano-technology Stoichiometry |
| Zdroj: | Solid State Communications. 275:12-15 |
| ISSN: | 0038-1098 |
| DOI: | 10.1016/j.ssc.2018.03.006 |
| Popis: | Recently, rare earth iridates, R2Ir2O7, with the pyrochlore structure have been intensively investigated due to their promise as either topological Mott insulators or Weyl semimetals. Single crystals of such pyrochlores with R = Nd, Sm, Eu, and Dy were prepared hydrothermally in sealed gold tubes at 975 K and show significantly higher electrical resistivities than previously reported for either crystals or polycrystalline samples. Furthermore, none of the present crystals exhibit the metal-insulator transition found for some samples of these phases. Lower resistivities are ascribed to lack of control of x and y in R2-xIr2O7-y in other more commonly used synthesis methods, yielding uncertainty in the Ir oxidation state. We also report resistivity of R2Ru2O7 crystals for R = Yb, Gd, Eu, and Nd, prepared in the same manner. These results suggest that the observed charge transport in hydrothermally grown iridate crystals is that of essentially stoichiometric phases and is consistent a with the existence of Weyl nodes. |
| Databáze: | OpenAIRE |
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