Carrier concentration dependence of spectral functions in strongly correlated system : Study by the dynamical mean field theory
Carrier concentration dependence of spectral functions in strongly correlated system : Study by the dynamical mean field theory
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强相关系统中谱函数的载流子浓度依赖性：动态平均场理论的研究
DOI：
10.1143/jpsj.66.2781
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发表时间：
1997
影响因子：
1.7
通讯作者：
D. Hirashima
中科院分区：
文献类型：
--
作者：
T. Mutou;Hideaki Takahashi;D. Hirashima
通过计算单粒子激发谱函数，研究了强关联绝缘体中载流子掺杂时巡游电子态的形成。在动力学平均场理论的框架下，我们将（1）量子Monte Carlo方法和（2）精确对角化方法应用于两带Hubbard模型。模型的参数选择，使未掺杂的系统是一个电荷转移型绝缘体。我们发现巡游态起源于d-和p-空穴杂化形成的局域单重态。我们还发现空穴掺杂和电子掺杂情况之间的不对称性：（1）在电子掺杂的情况下，没有观察到一个峰的化学势相反，空穴掺杂的情况下;（2）在电子掺杂的情况下的质量增强因子小于空穴掺杂的情况下。单粒子激发光谱和质量增强因子的结果进行了讨论，在光的实验和理论结果为高T c铜酸盐。
We study the formation of itinerant electronic states on carrier doping in a strongly correlated insulator by calculating one-particle-excitation spectral functions. We apply (1) the quantum Monte Carlo method and (2) the exact diagonalization method in the framework of the dynamical mean field theory to a two-band Hubbard model. The parameters of the model are chosen so that the undoped system is a charge-transfer-type insulator. We find that the itinerant states originate from local singlet states formed by hybridized d - and p -holes. We also find asymmetry between hole-doped and electron-doped cases: (1) in the electron-doped case a peak is not observed at the chemical potential in contrast to the hole-doped case; and (2) the mass-enhancement factor in the electron-doped case is smaller than that in the hole-doped case. The results of the one-particle-excitation spectrum and the mass-enhancement factor are discussed in the light of experimental and theoretical results for high- T c cuprates.