Fermi surface nesting and nanoscale fluctuating charge/orbital ordering in colossal magnetoresistive oxides
Fermi surface nesting and nanoscale fluctuating charge/orbital ordering in colossal magnetoresistive oxides
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DOI：
10.1126/science.1059255
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发表时间：
2001-05-25
期刊：
影响因子：
56.9
通讯作者：
Tokura, Y
中科院分区：
文献类型：
--
作者：
Chuang, YD;Gromko, AD;Tokura, Y
我们使用高分辨率角分辨光电子能谱揭示费米表面和关键的传输参数的层状庞磁阻氧化物La1.2Sr1.8Mn2O7的金属态。利用这些参数，计算出的面内电导率比测量的直流电导率大近一个数量级。这种差异可以通过包括赝能隙来解释，赝能隙在费米能量处去除了至少90%的光谱权重。赝能隙和许多其他性质的关键是平行的直费米面部分，这是非常容易受到嵌套不稳定性。这些嵌套不稳定性产生纳米级波动的电荷/轨道调制，这与Jahn-Teller扭曲合作，并与双交换所青睐的电子巡回竞争。
We used high-resolution angle-resolved photoemission spectroscopy to reveal the Fermi surface and key transport parameters of the metallic state of the layered colossal magnetoresistive oxide La1.2Sr1.8Mn2O7. With these parameters, the calculated in-plane conductivity is nearly one order of magnitude larger than the measured direct current conductivity. This discrepancy can be accounted for by including the pseudogap, which removes at least 90% of the spectral weight at the Fermi energy. Key to the pseudogap and to many other properties are the parallel straight Fermi surface sections, which are highly susceptible to nesting instabilities. These nesting instabilities produce nanoscale fluctuating charge/orbital modulations, which cooperate with Jahn-Teller distortions and compete with the electron itinerancy favored by double exchange.