Laboratoire des Solides Irradiés, CNRS UMR 7642, CEA-DSM-IRAMIS, École Polytechnique, Université Paris-Saclay, F-91128 Palaiseau, France.
European Theoretical Spectroscopy Facility (ETSF).
Phys Rev Lett. 2015 Mar 20;114(11):116402. doi: 10.1103/PhysRevLett.114.116402.
The effects of electron interaction on spectral properties can be understood in terms of coupling between excitations. In transition-metal oxides, the spectral function close to the Fermi level and low-energy excitations between d states have attracted particular attention. In this work we focus on photoemission spectra of vanadium dioxide over a wide (10 eV) range of binding energies. We show that there are clear signatures of the metal-insulator transition over the whole range due to a cross coupling of the delocalized s and p states with low-energy excitations between the localized d states. This coupling can be understood by advanced calculations based on many-body perturbation theory in the GW approximation. We also advocate the fact that tuning the photon energy up to the hard-x-ray range can help to distinguish fingerprints of correlation from pure band-structure effects.
电子相互作用对谱性质的影响可以根据激发之间的耦合来理解。在过渡金属氧化物中，费米能级附近的光谱函数和 d 态之间的低能激发引起了特别的关注。在这项工作中，我们集中研究了二氧化钒的光电子能谱，覆盖了很宽的（10 eV）结合能范围。我们表明，由于局域 d 态之间的低能激发与离域 s 和 p 态的交叉耦合，整个范围内都有金属-绝缘体转变的明显特征。这种耦合可以通过基于 GW 近似的多体微扰理论的先进计算来理解。我们还主张这样一个事实，即把光子能量调整到硬 X 射线范围，可以帮助区分相关的指纹与纯能带结构效应。
