Dynamical mean-field theory for the exciton Mott transition in electron–hole systems
Dynamical mean-field theory for the exciton Mott transition in electron–hole systems
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电子空穴系统中激子莫特跃迁的动态平均场理论
DOI：
10.1088/1742-6596/21/1/018
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
K. Asano
中科院分区：
文献类型：
--
作者：
T. Ogawa;Y. Tomio;K. Asano
在光激发绝缘体中的电子-空穴（e-h）系统中，可能发生激子Mott相变，这是一种典型的光致相变。为了理解激子Mott跃迁如何依赖于电子-空穴载流子密度和库仑关联，我们在电子-空穴对不凝聚的假设下，利用动力学平均场理论研究了电子-空穴双带Hubbard模型.得到了零温下相互作用平面上的相图。当电子带和空穴带都被半填充时，出现两种绝缘态：莫特-哈伯德绝缘体和双激子绝缘体。远离半填充，我们发现另一个绝缘相，激子样绝缘体，这是随后形成的非相干（非凝聚）的电子-氢对，而莫特-哈伯德绝缘体相消失。激子Mott跃迁为一级跃迁。线性光学极化率也进行了讨论。
In electron–hole (e–h) systems in photoexcited insulators, the exciton Mott transition may take place, which is a typical photoinduced phase transition. To understand how the exciton Mott transition depends on the e–h carrier density and the Coulomb correlation, we study an e–h two-band Hubbard model by means of the dynamical mean-field theory assuming that electron–hole pairs do not condense. The phase diagram on the plane of interactions at zero temperature is obtained. When both electron and hole bands are half-filled, two types of insulating states appear: the Mott–Hubbard insulator and the biexciton-like insulator. Away from half-filling we find another insulating phase, the exciton-like insulator, which is followed by the formation of incoherent (not condensed) e–h pairs, while the Mott–Hubbard insulator phase disappears. The exciton Mott transition is found to be the first-order transition. Linear optical susceptibilities are also discussed.