Destruction of the Mott Insulating Ground State of Ca 2 R u O 4 by a Structural Transition
نویسندگان
چکیده
We report a first-order phase transition at TM=357 K in single crystal Ca2RuO4, an isomorph to the superconductor Sr2RuO4. The discontinuous decrease in electrical resistivity signals the near d e struction of the Mott insulating phase and is triggered by a s t ructural transition from the low temperature orthorhombic to a high temperature tetragonal phase. The magnetic susceptibility, which is temperature dependent but not Curie-like decreases abruptly at TM and becomes less temperature dependent. Unlike most insulator t o metal transitions, the system is not magnetically ordered in e i ther phase, though the Mott insulator phase is antiferromagnetic below TN=110 K.
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