Binding energies of exciton complexes in transition metal dichalcogenide monolayers and effect of dielectric environment
Binding energies of exciton complexes in transition metal dichalcogenide monolayers and effect of dielectric environment
复制标题
DOI：
10.1103/physrevb.92.205418
复制
发表时间：
2015-11-16
影响因子：
3.7
通讯作者：
Komsa, Hannu-Pekka
中科院分区：
文献类型：
--
作者：
Kylanpaa, Ilkka;Komsa, Hannu-Pekka
用密度泛函理论和准积分蒙特卡罗方法研究了二维过渡金属MoS_2、MoSe_2、MoTe_2、WS_2和WSe_2中的激子、三子、双激子和激子-三子络合物，以精确地计算粒子-粒子关联。此外，通过修正粒子间的有效相互作用势，研究了介电环境对激子复合体性质的影响。计算的激子和三子结合能与以前的实验和计算结果一致，发现双激子和激子-三子络合物等较大的系统高度稳定。双激子的结合能与三子的结合能相似或高于三子的结合能，但三子的结合能对介电环境的依赖性明显强于双激子。因此，随着环境介电常数的增加，激子-三子复合体“解离”为双激子，而不是激子和三子。
Excitons, trions, biexcitons, and exciton-trion complexes in two-dimensional transition metal dichalcogenide sheets of MoS2, MoSe2, MoTe2, WS2, and WSe2 are studied by means of density functional theory and pathintegral Monte Carlo method in order to accurately account for the particle-particle correlations. In addition, the effect of dielectric environment on the properties of these exciton complexes is studied by modifying the effective interaction potential between particles. Calculated exciton and trion binding energies are consistent with previous experimental and computational studies, and larger systems such as biexciton and exciton-trion complex are found highly stable. Binding energies of biexcitons are similar to or higher than those of trions, but the binding energy of the trion depends significantly stronger on the dielectric environment than that of biexciton. Therefore, as a function of an increasing dielectric constant of the environment the exciton-trion complex "dissociates" to a biexciton rather than to an exciton and a trion.