Analytical approach to excitonic properties of MoS2
Analytical approach to excitonic properties of MoS2
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DOI：
10.1103/physrevb.89.125309
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发表时间：
2014-03-20
影响因子：
3.7
通讯作者：
Malic, Ermin
中科院分区：
文献类型：
--
作者：
Berghaeuser, Gunnar;Malic, Ermin
我们对单层二硫化钼的光吸收光谱进行了分析研究。基于密度矩阵的形式主义，我们的方法给出了洞察激子跃迁的微观起源，它们的相对振子强度，和结合能。我们给出了载波光耦合元件的解析表达式，它包含了光学选择规则，并很好地描述了MoS2中的谷选择性偏振。与实验结果一致，我们发现由于有效的库仑相互作用，形成了强束缚的电子空穴对。MoS2的吸收光谱的特征在于对应于A和B激子的两个明显的峰。对于SiO2衬底上的MoS2，其特征在于结合能分别为455 meV和465 meV。我们的计算揭示了它们的相对振子强度，并预测在更高的能量下出现进一步的低强度激子跃迁。所提出的方法适用于其他过渡金属二硫族化物，并可以扩展到三电子和双激子效应的调查。
We present an analytical investigation of the optical absorption spectrum of monolayer molybdenum-disulfide. Based on the density matrix formalism, our approach gives insights into the microscopic origin of excitonic transitions, their relative oscillator strength, and binding energy. We show analytical expressions for the carrier-light coupling element, which contains the optical selection rules and describes well the valley-selective polarization in MoS2. In agreement with experimental results, we find the formation of strongly bound electron-hole pairs due to the efficient Coulomb interaction. The absorption spectrum of MoS2 features two pronounced peaks corresponding to the A and B exciton. For MoS2 on a SiO2 substrate, these are characterized by binding energies of 455 meV and 465 meV, respectively. Our calculations reveal their relative oscillator strength and predict the appearance of further low-intensity excitonic transitions at higher energies. The presented approach is applicable to other transition metal dichalcogenides and can be extended to investigations of trion and biexcitonic effects.