摘 要 利用高温高压条件，制备了(SrCa)CrO3系列带宽可调型的钙钛矿Mott化合物。在10 GPa的外加压力下，观察到SrCrO3的绝缘体-金属化相变。原位高压X射线衍射实验表明，Sr/CaCrO3晶体结构在0-9 GPa压力范围内保持稳定。但SrCrO3在4 GPa时存在着电子结构变化所引起的等结构相变，表现为体弹性模量的反常软化。此外，由于电子关联效应，磁性和热输运性质的测试结果表明了材料的奇异电子态特征。
关键词 带宽调控型Mott 化合物，高压合成，高压金属化相变
High-pressure synthesis and metallization of a new type of bandwidth-controlled Mott compounds
LONG You-Wen1YANG Liu-Xiang1JIN Chang-Qing1,ZHOU Jian-Shi2J B Goodenough2
(1 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China)
(2 Texas Materials Institute, University of Texas at Austin, USA)
Abstract A series of bandwidth-controlled (SrCa)CrO3Mott compounds with perovskite crystal structure were synthesized by using high pressure and high temperature conditions. An insulator-to-metal transition was observed in SrCrO3at 10 GPa. In situ high-pressure X-ray diffraction shows that the crystal structures of Sr/CaCrO3remain stable in the same pressure range, but there exists an isostructural phase transition as a result of the change of electronic structure in SrCrO3at 4 GPa, accompanied by an unusual softening of bulk modulus. In addition, the magnetic and thermal transport properties indicate a strange electronic state, due to the strong correlated electron effects in these materials. ......