论文标题
库仑互动对有机狄拉克电子系统的Seebeck系数$α$ - （BEDT-TTF）$ _ 2 $ i $ _3 $
Effect of Coulomb Interaction on Seebeck Coefficient of Organic Dirac Electron System $α$-(BEDT-TTF)$_2$I$_3$
论文作者
论文摘要
在最近的热电效应研究的结果中，我们根据扩展的哈伯德模型来显示库仑相互作用对Seebeck系数的影响，该模型描述了略微掺杂的有机狄拉克电子系统的电子状态，$α$ - （BEDTT-TTF）$ _ 2 $ _ 2 $ i $ _3 $。我们的结果表明，库仑相互作用的哈特里术语增强了能带结构的电子孔不对称，并改变了杂质散射的弛豫时间的能量依赖性，这反映了状态密度的形状。因此，Seebeck系数表现出非单调的$ t依赖性，与实验结果一致。此外，我们还表明，使用线性反应理论计算出的Seebeck系数和HALL系数的迹象不一定与具有电子孔不对称的修改的Weyl模型相对应。这些结果指出，通过强库仑相互作用改变电子孔不对称性，有可能控制狄拉克电子系统中Seebeck系数的符号和值。
Motivated by the results of recent thermoelectric effect studies, we show the effects of Coulomb interactions on the Seebeck coefficient based on an extended Hubbard model that describes the electronic states of a slightly doped organic Dirac electron system, $α$-(BEDT-TTF)$_2$I$_3$. Our results indicate that the Hartree terms of the Coulomb interactions enhance the electron-hole asymmetry of the energy band structure and change the energy dependence of the relaxation time from impurity scattering, which reflects the shape of the density of states. Thus, the Seebeck coefficient exhibits a non-monotonic $T$ dependence which qualitatively agrees with the experimental results. Furthermore, we also show that the signs of the Seebeck coefficient and the Hall coefficient calculated by linear response theory do not necessarily correspond to the sign of the chemical potential using a modified Weyl model with electron-hole asymmetry. These results point out that changing the electron-hole asymmetry by strong Coulomb interaction has the potential to controllable the sign and value of the Seebeck coefficient in the Dirac electron systems.
