Phase diagram for the exciton Mott transition in infinite-dimensional electron–hole systems
Phase diagram for the exciton Mott transition in infinite-dimensional electron–hole systems
复制标题
无限维电子空穴系统中激子莫特跃迁的相图
DOI：
10.1016/j.jlumin.2004.09.060
复制
发表时间：
2004
影响因子：
3.6
通讯作者：
T. Ogawa
中科院分区：
文献类型：
--
作者：
Y. Tomio;T. Ogawa
为了理解三维电子-空穴系统中激子莫特跃迁的本质，我们研究了具有电子-电子（空穴-空穴）排斥力U和电子-空穴吸引力-U′相互作用的无限维两能带哈伯德模型的金属-绝缘体跃迁。通过使用动态平均场理论，假设电子空穴对不凝聚，可以获得 U-U' 平面中的相图（在无限维度上是精确的）。当电子和空穴带都半充满时，出现两种类型的绝缘态：U>U'的莫特-哈伯德绝缘体和U<U'的类双激子绝缘体。即使远离半填充，我们也发现了类激子或类双激子绝缘体与金属态之间的相变。该跃迁可归因于激子莫特跃迁，而莫特-哈伯德跃迁不存在。
To understand the essence of the exciton Mott transition in three-dimensional electron–hole systems, the metal–insulator transition is studied for a two-band Hubbard model in infinite dimensions with interactions of electron–electron (hole–hole) repulsion U and electron–hole attraction -U′. By using the dynamical mean-field theory, the phase diagram in the U–U′plane is obtained (which is exact in infinite dimensions) assuming that electron–hole pairs do not condense. When both electron and hole bands are half-filled, two types of insulating states appear: the Mott–Hubbard insulator for U>U′and the biexciton-like insulator for U<U′. Even when away from half-filling, we find the phase transition between the exciton- or biexciton-like insulator and a metallic state. This transition can be assigned to the exciton Mott transition, whereas the Mott–Hubbard transition is absent.