Exciton-polarons in doped semiconductors in a strong magnetic field
Exciton-polarons in doped semiconductors in a strong magnetic field
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DOI：
10.1103/physrevb.97.235432
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发表时间：
2018-06-21
影响因子：
3.7
通讯作者：
MacDonald, Allan H.
中科院分区：
文献类型：
--
作者：
Efimkin, Dmitry K.;MacDonald, Allan H.
在以前的工作中，我们认为，中度掺杂的二维半导体的光学性质可以描述在激子的相互作用与一个简并的费米海的额外的电荷载流子的装饰。这些相互作用将裸激子分裂成吸引和排斥激子-极化子分支。耦合系统的集体激发是束缚激子和单个电子与激子相互作用的非束缚态的多体推广。在本文中，我们考虑激子极化子在存在的外部磁场量子化的费米海中的电子的动能。我们的理论方法是基于转换到一个新的基础上，尊重潜在的对称性的磁翻译。我们发现，吸引激子极化子分支是只有微弱的磁场的影响，而排斥分支表现出磁振荡和分裂成离散的峰，反映组合激子回旋共振。
In previous work, we have argued that the optical properties of moderately doped two-dimensional semiconductors can be described in terms of excitons dressed by their interactions with a degenerate Fermi sea of additional charge carriers. These interactions split the bare exciton into attractive and repulsive exciton-polaron branches. The collective excitations of the coupled system are many-body generalizations of the bound trion and unbound states of a single electron interacting with an exciton. In this paper, we consider exciton-polarons in the presence of an external magnetic field that quantizes the kinetic energy of the electrons in the Fermi sea. Our theoretical approach is based on a transformation to a new basis that respects the underlaying symmetry of magnetic translations. We find that the attractive exciton-polaron branch is only weakly influenced by the magnetic field, whereas the repulsive branch exhibits magnetic oscillations and splits into discrete peaks that reflect combined exciton-cyclotron resonance.