Emergence of a Diffusive Metal State with No Magnetic Order near the Mott Transition in Frustrated Pyrochlore-Type Molybdates
Emergence of a Diffusive Metal State with No Magnetic Order near the Mott Transition in Frustrated Pyrochlore-Type Molybdates
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DOI：
10.1103/physrevlett.102.136407
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发表时间：
2009-04-03
影响因子：
8.6
通讯作者：
Tokura, Y.
中科院分区：
文献类型：
--
作者：
Iguchi, S.;Hanasaki, N.;Tokura, Y.
在热释胆型R(2)Mo(2)O(7)(R为稀土金属离子)中，电子相关驱动的金属绝缘体(Mott)相变伴随着磁态从铁磁到自旋玻璃的转变，这是由于受阻晶格上竞争的双交换和超交换作用所致。然而，通过对具有Mott临界性的化合物施加高压，观察到一种新的独特的顺磁金属相，其高阻几乎与温度无关，接近Ioffe-Regel极限。根据磁阻挡局域S=12自旋的扩展双交换模型，讨论了这种反常扩散金属态可能的非费米液体性质。
The electron-correlation driven metal-insulator (Mott) transition in pyrocholore-type R(2)Mo(2)O(7)(R being rare-earth-metal ions) is accompanied by the change of the magnetic state from ferromagnetic to spin glass due to the competing double-exchange and superexchange interactions on the frustrated lattice. By application of high pressures on the compounds with Mott criticality, however, a new unique paramagnetic metal phase is observed to show up with nearly temperature-independent high resistivity close to the Ioffe-Regel limit. A possible non-Fermi-liquid character of this anomalously diffuse metallic state is argued in terms of the extended double-exchange model with the magnetically frustrated local S=12 spins.