Structurally-driven metal–insulator transition in Ca2Ru1−xCrxO4 (0≤x<0.14) A single crystal X-ray diffraction study

Correlation between structure and transport properties are investigated in high-quality single-crystals of Ca2Ru1 xCrxO4 with 0oxo0.14 using single crystal X-ray diffraction and by electronic studies. The parent compound was known to exhibit an intriguing first-order structurally driven metal–insulator (MI) transition at 357 K. Upon chromium doping on the ruthenium site, the metal–insulator transition temperature (TMI) was drastically reduced, and is related to the competition between structural changes that occur upon Cr doping and with decreasing temperature. A strong suppression of structural distortions with increasing Cr substitution was identified. No clear TMI can be observed when x413.5% and the system behaves as an insulator. Such a large, sharp metal–insulator transition and tuneable transition temperature may have potential applications in electronic devices. & 2011 Elsevier Inc. All rights reserved.