Mohamed Mansour, May Matthias M, Kanis Michael, Brützam Mario, Uecker Reinhard, van de Krol Roel, Janowitz Christoph, Mulazzi Mattia
Institut für Physik, Humboldt-Universität zu Berlin D-12489 Berlin Germany
Departement of Physics, Faculty of Science, Assiut University 71515 Assiut Egypt.
RSC Adv. 2019 May 17;9(27):15606-15614. doi: 10.1039/c9ra01092k. eCollection 2019 May 14.
We experimentally investigated the electronic structure of Mo-doped BiVO high-quality single-crystals with synchrotron radiation-excited angle-resolved photoelectron spectroscopy (ARPES). By photon-energy dependent ARPES, we measured the bulk-derived valence band dispersion along the direction normal to the (010) cleavage plane, while the dispersion along the in-plane directions is obtained by angle-dependent measurements at fixed photon energy. Our data show that the valence band has a width of about 4.75 eV and is composed of many peaks, the two most intense have energies in good agreement with the theoretically calculated ones. A non-dispersive feature is observed in the fundamental gap, which we attribute to quasiparticle excitations coupling electrons and phonons, polarons. The determination of the polaron peak binding energy and bulk band gap allows to fix the value of the theoretical mixing parameter necessary in hybrid Hartree-Fock calculations to reproduce the experimental data. The attribution of the in-gap peak to polarons is strengthened by our discussion in the context of experimental transport data and theory.
我们采用同步辐射激发角分辨光电子能谱（ARPES）对掺钼的BiVO高质量单晶的电子结构进行了实验研究。通过依赖光子能量的ARPES，我们测量了沿垂直于(010)解理面方向的体相衍生价带色散，而在固定光子能量下通过角度依赖测量获得面内方向的色散。我们的数据表明，价带宽度约为4.75 eV，由许多峰组成，其中两个最强峰的能量与理论计算值吻合良好。在基本能隙中观察到一个非色散特征，我们将其归因于耦合电子和声子的准粒子激发，即极化子。确定极化子峰结合能和体带隙有助于确定混合Hartree-Fock计算中重现实验数据所需的理论混合参数值。结合实验输运数据和理论进行讨论，进一步证实了能隙峰为极化子的归属。
