Anomalous state sandwiched between Fermi liquid and charge ordered Mott-insulating phases of Ti4O7.
Anomalous state sandwiched between Fermi liquid and charge ordered Mott-insulating phases of Ti4O7.
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DOI：
10.1103/physrevlett.104.106401
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发表时间：
2009-02
影响因子：
8.6
通讯作者：
M. Taguchi;A. Chainani;M. Matsunami;R. Eguchi;Y. Takata;M. Yabashi;K. Tamasaku;Y. Nishino;T. I
中科院分区：
文献类型：
--
作者：
M. Taguchi;A. Chainani;M. Matsunami;R. Eguchi;Y. Takata;M. Yabashi;K. Tamasaku;Y. Nishino;T. I
在T(C1)约142K和T(C2)=154K的温度下，Magnéli相Ti(4)O(7)的电阻率出现两个急剧的跃迁，并伴随着耦合的结构转变。我们用7 eV激光、软X射线和硬X射线光电子能谱(PES)研究了这两个转变过程中的电子结构变化。Ti2p-3D共振PES和HX PES显示出清晰的金属费米边缘和T(C2)以上的混合价态。T(C1)以下的低温相显示出大约100 meV的明显绝缘间隙。T(C1)和T(C2)之间的中间位相表示与剩余相干态共存的伪隙。HX、PES和互补计算证实了强关联中间相的相干屏蔽。结果表明，在Ti(4)O(7)中存在一个夹在混合价费米液体和电荷有序Mott绝缘相之间的高度反常状态。
The Magnéli phase Ti(4)O(7) exhibits two sharp jumps in resistivity with coupled structural transitions as a function of temperature at T(c1) approximately 142 K and T(c2) = 154 K. We have studied electronic structure changes across the two transitions using 7 eV laser, soft x-ray, and hard x-ray (HX) photoemission spectroscopy (PES). Ti 2p-3d resonant PES and HX PES show a clear metallic Fermi edge and mixed valency above T(c2). The low temperature phase below T(c1) shows a clear insulating gap of approximately 100 meV. The intermediate phase between T(c1) and T(c2) indicates a pseudogap coexisting with remnant coherent states. HX PES and complementary calculations have confirmed the coherent screening in the strongly correlated intermediate phase. The results suggest the existence of a highly anomalous state sandwiched between the mixed-valent Fermi liquid and charge ordered Mott-insulating phase in Ti(4)O(7).