Reconstruction of Band Structure Induced by Electronic Nematicity in an FeSe Superconductor
Reconstruction of Band Structure Induced by Electronic Nematicity in an FeSe Superconductor
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DOI：
10.1103/physrevlett.113.237001
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发表时间：
2014-12-05
影响因子：
8.6
通讯作者：
Takahashi, T.
中科院分区：
文献类型：
--
作者：
Nakayama, K.;Miyata, Y.;Takahashi, T.
我们用高分辨角分辨光电子能谱研究了FeSe超导体（T-c近似于8 K），该超导体在T-s近似于90 K时发生四方相到正交相的结构转变。在低温下，我们发现在布里渊区的M点处的能带分裂高达50 meV，这可能是由于形成电子驱动的基态引起的。这种带分裂持续到T类似于110 K，略高于Ts，这表明结构转变是由电子向列性触发的。我们还发现，在低温下，带分裂引起的货车霍韦奇异的费米能量在5 meV。这一结果有力地表明，这种不寻常的电子状态是导致FeSe非常规超导性的原因。
We have performed high-resolution angle-resolved photoemission spectroscopy on an FeSe superconductor (T-c similar to 8 K), which exhibits a tetragonal-to-orthorhombic structural transition at T-s similar to 90 K. At low temperature, we found splitting of the energy bands as large as 50 meVat the M point in the Brillouin zone, likely caused by the formation of electronically driven nematic states. This band splitting persists up to T similar to 110 K, slightly above T-s, suggesting that the structural transition is triggered by the electronic nematicity. We have also revealed that at low temperature the band splitting gives rise to a van Hove singularity within 5 meV of the Fermi energy. The present result strongly suggests that this unusual electronic state is responsible for the unconventional superconductivity in FeSe.