Habenicht Carsten, Schuster Roman, Knupfer Martin, Büchner Bernd
IFW Dresden, Institute for Solid State Research, Helmholtzstrasse 20, 01069 Dresden, Germany.
J Phys Condens Matter. 2018 May 23;30(20):205502. doi: 10.1088/1361-648X/aabd02. Epub 2018 Apr 10.
We have investigated indirect excitons in bulk 2H-MoS using transmission electron energy-loss spectroscopy. The electron energy-loss spectra were measured for various momentum transfer values parallel to the [Formula: see text] and [Formula: see text] directions of the Brillouin zone. The results allowed the identification of the indirect excitons between the valence band K and conduction band Λ points, the Γ and K points as well as adjacent K and [Formula: see text] points. The energy-momentum dispersions for the K -Λ, Γ-K and K -[Formula: see text] excitons along the [Formula: see text] line are presented. The former two transitions exhibit a quadratic dispersion which allowed calculating their effective exciton masses based on the effective mass approximation. The K -[Formula: see text] transition follows a more linear dispersion relationship.
我们使用透射电子能量损失谱研究了块状2H-MoS中的间接激子。针对与布里渊区的[公式：见正文]和[公式：见正文]方向平行的各种动量转移值测量了电子能量损失谱。结果使得能够识别价带K和导带Λ点、Γ和K点以及相邻的K和[公式：见正文]点之间的间接激子。给出了沿[公式：见正文]线的K-Λ、Γ-K和K-[公式：见正文]激子的能量-动量色散关系。前两个跃迁呈现出二次色散关系，这使得能够基于有效质量近似计算它们的有效激子质量。K-[公式：见正文]跃迁遵循更线性的色散关系。
