Tanabe Iori, Komesu Takashi, Le Duy, Rawal Takat B, Schwier Eike F, Zheng Mingtian, Kojima Yohei, Iwasawa Hideaki, Shimada Kenya, Rahman Talat S, Dowben Peter A
Department of Physics and Astronomy, Theodore Jorgensen Hall, 855 N 16th, University of Nebraska, Lincoln, NE 68588-0299, USA.
J Phys Condens Matter. 2016 Sep 1;28(34):345503. doi: 10.1088/0953-8984/28/34/345503. Epub 2016 Jun 30.
The orbital symmetry of the band structure of 2H-WSe2(0 0 0 1) has been investigated by means of angle-resolved photoelectron spectroscopy (ARPES) and density functional theory (DFT). The WSe2(0 0 0 1) experimental band structure is found, by ARPES, to be significantly different for states of even and odd reflection parities along both the [Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text] lines, in good agreement with results obtained from DFT. The light polarization dependence of the photoemission intensities from the top of the valence band for bulk WSe2(0 0 0 1) is explained by the dominance of W 5[Formula: see text] states around the [Formula: see text]-point and W 5d xy states around the [Formula: see text]-point, thus dominated, respectively, by states of even and odd symmetry, with respect to the [Formula: see text]-[Formula: see text] line. The splitting of the topmost valence band at [Formula: see text], due to spin-orbit coupling, is measured to be 0.49 ± 0.01 eV, in agreement with the 0.48 eV value from DFT, and prior measurements for the bulk single crystal WSe2(0 0 0 1), albeit slightly smaller than the 0.513 ± 0.01 eV observed for monolayer WSe2.
通过角分辨光电子能谱（ARPES）和密度泛函理论（DFT）研究了2H-WSe2(0 0 0 1)能带结构的轨道对称性。通过ARPES发现，WSe2(0 0 0 1)的实验能带结构在沿[公式：见原文]-[公式：见原文]和[公式：见原文]-[公式：见原文]线的偶宇称和奇宇称状态下有显著差异，这与DFT得到的结果高度一致。对于体相WSe2(0 0 0 1)价带顶的光电子发射强度的光偏振依赖性，可通过在[公式：见原文]点附近W 5[公式：见原文]态的主导以及在[公式：见原文]点附近W 5d xy态的主导来解释，因此分别由相对于[公式：见原文]-[公式：见原文]线具有偶对称和奇对称的状态主导。由于自旋轨道耦合，在[公式：见原文]处最顶层价带的分裂测量值为0.49±0.01 eV，与DFT得到的0.48 eV值一致，也与之前对体相单晶WSe2(0 0 0 1)的测量值一致，尽管略小于在单层WSe2中观察到的0.513±0.01 eV。
