论文标题
从动量分辨的电子能量损失光谱（M-EELS）中提取相关效应：分散性扭结在Bi $ _ {2.1} $ _ {2.1} $ sr $ _ {1.9} $ CACU $ _2 $ _2 $ _ {8+X} $中的协同起源
Extracting correlation effects from Momentum-Resolved Electron Energy Loss Spectroscopy (M-EELS): Synergistic origin of the dispersion kink in Bi$_{2.1}$Sr$_{1.9}$CaCu$_2$O$_{8+x}$
论文作者
论文摘要
我们在BI2.1SR1.9CACU2O8+X上采用动量分辨的电子能量损失光谱（M-EELS）来解决电子分散中的扭结特征问题，在库酸酯中广泛观察到。为此，我们利用GW近似将M-Eels中测量的密度响应函数与自能源，从声子，电子中分离出贡献以及有效相互作用对衰减速率的动量依赖性。由于电子 - 音波耦合而引起的M-eels光谱中存在的语音贡献导致相应的单粒子光谱在40 MeV和80 MeV之间的相应单粒子光谱中，与掺杂水平无关。我们发现动量空间中的排斥相互作用常数能够产生归因于ARPES中的声子的扭结。因此，我们对M-eels光谱的分析表明，局部排斥性相互作用是增强库酸酯中电子音波偶联的光谱特征的因素。我们得出的结论是，丘比特中的扭结特征的强度取决于电子 - 音波耦合和电子电子相互作用的联合作用。
We employ Momentum-Resolved Electron Energy Loss Spectroscopy (M-EELS) on Bi2.1Sr1.9CaCu2O8+x to resolve the issue of the kink feature in the electron dispersion widely observed in the cuprates. To this end, we utilize the GW approximation to relate the density response function measured in in M-EELS to the self-energy, isolating contributions from phonons, electrons, and the momentum dependence of the effective interaction to the decay rates. The phononic contributions, present in the M-EELS spectra due to electron-phonon coupling, lead to kink features in the corresponding single-particle spectra at energies between 40 meV and 80 meV, independent of the doping level. We find that a repulsive interaction constant in momentum space is able to yield the kink attributed to phonons in ARPES. Hence, our analysis of the M-EELS spectra points to local repulsive interactions as a factor that enhances the spectroscopic signatures of electron-phonon coupling in cuprates. We conclude that the strength of the kink feature in cuprates is determined by the combined action of electron-phonon coupling and electron-electron interactions.
